If the only way to save the world was to destroy what you loved most, would you do it?
The clock is ticking. Everyone must choose.
Passion. Power. Secrets. Enchantment.
THE INFERNAL DEVICES ARE WITHOUT PITY.
THE INFERNAL DEVICES ARE WITHOUT REGRET.
THE INFERNAL DEVICES ARE WITHOUT NUMBER.
THE INFERNAL DEVICES WILL NEVER STOP COMING.
Tessa Gray should be happy — aren't all brides happy? Yet as she prepares for her wedding to Jem Carstairs, a net of shadows begins to tighten around the Shadowhunters of the London Institute. A new demon appears, one linked by blood and secrecy to the Magister, the man who plans to use his army of pitiless automatons, the Infernal Devices, to destroy the Shadowhunters. He needs only one last item to complete his plan of destruction.
He needs Tessa.
Tessa knows Axel Mortmain, the Magister, is coming for her, but not where or when he will strike. Charlotte Branwell, the head of the London Institute, is desperate to find Mortmain first. And the boys who lay equal claim to Tessa's heart, Jem and Will, will do anything to save her. For though Tessa and Jem are now engaged, and Will knows he should force himself to find someone else to care for, he is as much in love with her as ever.
In the last words of a dying Shadowhunter reside the clue that might lead Tessa and her friends to Mortmain. But the Shadowhunters of the London Institute cannot stand alone, and in their homeland of Idris, the ruling body of the Clave doubt their claims that Mortmain is coming. Deserted by those who should be their allies and with their enemies closing in, the Shadowhunters find themselves trapped when Mortmain seizes the medicine which is all that is keeping Jem alive. With his best friend at death's door it is up to Will to risk everything to save the woman they both love.
To buy Will time, the warlock Magnus Bane joins with Henry Branwell to create a device that could help them to defeat the Magister. As those who love Tessa work to save her, and the future of the Shadowhunters that resides with her, Tessa realizes that the only person who can save her is herself—for in the discovery of her own true nature, Tessa begins to learn that she is more powerful than she ever dreamed possible. But can a single girl, even one who can command the power of angels, face down an entire army?
Danger and betrayal, secrets and enchantment, and the tangled threads of love and loss intertwine as the Shadowhunters are pushed to the very brink of destruction in the breathtaking conclusion to the Infernal Devices trilogy.
Aloysius Starkweather's granddaughter Adele Starkweather is set to receive her first Mark. Her grandfather informs her that she will first receive the Strength rune; because of her fragility and delicacy, she might not be able to handle the Voyance rune. Adele fearfully and reluctantly lets the Silent Brothers perform the ritual, soothed by her beloved grandfather. However, Adele cries out in agony, but it is too late when they realize that she cannot bear the Marks, and she dies.
Charlotte Branwell interrupts a young Will's target practice in the training room to introduce to him the new ward, Jem. Jem is thin and pale, with the effects of the yin fen just showing. Will, as usual, is rude to the boy and calls him sickly, as if "doddering to the grave," much to Charlotte's disappointment. However, Jem is seemingly unaffected by his words and points out to Will that he is indeed dying. Will apologizes and expresses his concern. Jem tells him not to feel sorry for him. He tells Will that he is a good shot and can help him improve his skills. Much to Charlotte's surprise, Will agrees to train with him.
Present: London, 1878
Tessa is trying out her gold wedding gown when Jem knocks on the door. The superstitious and pregnant Charlotte insists that Tessa hide so Jem does not see her in her wedding dress, as it is bad luck among Shadowhunters. Jem tells them that Gabriel Lightwood is in the Institute, "making the most dreadful row."
Meanwhile, in the training room, Will is training his sister Cecily. Even two months after her arrival, Will is still seemingly not pleased that she is there, while Cecily has already adjusted, though is still trying to get Will to write to their family. Cecily has practiced knife-throwing in secret, so she confidently bet Will that he must write to them if she hits the target thrice; she does, though Will twists her words by saying that while he will write them, he did not agree to send it. Cecily is dejected, but before the two can argue any further, Jem interrupts them and tells them that Gabriel is making a scene downstairs.
Elsewhere, Sophie is bringing Gideon scones he asked for, along with some food Bridget prepared for him. He tries to talk to her, but Sophie is determined to avoid him, telling herself that her feelings for him will get them nowhere as she is a mundane servant, and that she has everything to lose, while Gideon does not. Gideon is just about to ask Sophie something before Henry arrives to tell Gideon about Gabriel's arrival.
With everyone gathered at the entrance of the Institute,a harried, gore-covered Gabriel, upon seeing Gideon, finally tells them his problem: their father, Benedict, has turned into a demon, in the form of a worm. Gabriel had escaped from it just as the worm attacked him. Will informs them that Benedict is in the last stage of his illness. The Shadowhunters decide to go over to the Chiswick Manor where Benedict is hiding. Initially, Will protests when Cecily volunteers to accompany them, arguing that she was barely fifteen-years old and did not have enough training, but he is overridden by Henry. Will, Jem, Gabriel, Gideon, Henry, Cecily and Tessa then proceed to the manor, and once there, spread out in search of the worm. They come across a hysterical Tatiana Blackthorn who informs them that she was there to call upon her father. However, when she reached the manor, a giant worm had seized her husband Rupert and taken him away. Fearing the worst, the group moves ahead.
When they finally encounter Benedict, now the worm, seems to overpower them but Cecily, despite being hardly trained, climbs over a tree and drops down on the monster, effectively distracting and simultaneously stabbing it. Gabriel is the one who kills Benedict with an arrow through the eye. Will is horrified, and reprimands her. Gabriel cuts off Will's scolding, saying "That was one of the bravest things I've seen a Shadowhunter do" and is seemingly mesmerized by her.
Tessa, once she has deposited Tatiana to the safety of their carriage, ventures into the house, when she hears Henry's scream. She quickly helps him dispatch the demon in Benedict's study, and find several of Benedict's diaries and journals, and also an inscription on the walls of the room, stating,
The Infernal Devices are without pity.
The Infernal Devices are without regret.
The Infernal Devices are without number.
The Infernal Devices will never stop coming.
In the greenhouse, Jem has a coughing fit and collapses on the ground. Will rushes to his side and they all proceed back to the Institute. A distraught Tessa is comforted by Will, while the Silent Brothers treat Jem.
Meanwhile, unbeknown to the residents of the Institute, there is an issue of who is going to become the next Consul. While the members of The Council suggest Charlotte, Consul Wayland disagrees due to not wanting to lose his own legacy, and suggests his nephew George Penhallow instead.
Charlotte tells Gabriel that he is welcome to stay in the Institute as long as he wished to, so long as he was loyal to them. Sometime later, Sophie carries a tray of scones to Gideon's room, where she finds Gabriel sprawled on the bed, sleeping soundly. Gideon and her get intimate, and fall on the floor, where she finds a veritable amount of scones hidden underneath the bed. She snaps at Gideon for being insensitive and leaves.
Will discovers that Jem has been taking extra doses of yin fen, a process that would accelerate his death. Jem explains it's because he told Tessa his love for her was making him stronger, and he feared Tessa would think his love for her was lessening, if he were to stop consuming the drug in considerable amounts. Not wishing to waste time, he immediately proceeds to Whitechapel to collect as much drug as possible.
Cecily is training in the Institute when she is approached by Gabriel. He points out that she needs to take some training and also informs her of Will's hurried departure. Cecily immediately follows her brother, and even on being caught by the latter, chooses to accompany him. There, he confesses that Cecily is his weakness, however this did not discourage the latter.
At about midnight, a distraught Will tells Tessa that someone has bought up all the yin fen in the country—he'd spent that entire evening visiting suppliers, but they were all out of stock. He also informs her that Jem had permitted him to search for a cure. They seek out Magnus for help, and visit his temporary residence in Chelsea. They are greeted by Woolsey Scott and Will explains the issue to Magnus. Before the warlock can reply, Woosley comments on how Will would gain Tessa after Jem's death. This enrages Will and he is dragged out of the room by Magnus, just as he starts a fight. Meanwhile Tessa threatens Woolsey using a fire poker to behave himself.
Once in the library, Will begs for Magnus' help, and the latter agrees. He also gives Will a necklace that once belonged to Camille Belcourt. In the living room, Woolsey catches Tessa off her guard as he states that he knows about her affection towards Will. Later, Magnus sends them off with a promise of informing them if he finds something. Tessa comforts Will in the carriage and Magnus feels heartbroken for them.
The Inquisitor writes a letter to the Consul, hoping the latter could explain his hesitation at appointing Charlotte as the next Consul. The Consul's reply states that he does not wish to hand over the charge of the Nephilim to a woman who s passionate and acts rather impulsively.
Charlotte informs the Lightwood brothers that Tatiana has demanded Reparations. Gabriel is horrified and agrees to pay the amount when Consul Wayland calls upon the London Shadowhunters. He reprimands Charlotte for acting of her own free will, instead of informing The Clave. He is extremely livid about the fact that his authority had been undermined and Benedict's papers had been taken by Charlotte, which was against the protocol. He takes Gabriel and Gideon with him, stating that the Silent Brothers needed to investigate and record their statements. However, instead of taking them to the Silent City, he lures them to a club, where he blackmails them to spy on Charlotte and go through her correspondence. He wanted the Lightwoods to find some incriminating evidence against her. In return for this task, the Consul would return them all of Benedict's properties. Gabriel agrees to the terms and explains later, that he has decided to write irrelevant letters to the Consul, hoping he would give up on them and leave them alone.
Cecily is training once again in the Institute, feeling furious about her brother's stubbornness to not contact their parents. She is accosted by Gabriel, and he offers to train her. She finds that she doesn't mind his company, unlike her brother. Just as they are about to begin their practice, Will interrupts them and tells Gabriel not to take advantage of his sister. Cecily asks him if it is necessary for him to behave this way and Will retorts that Gabriel was not to be tested.
Mortmain sends a letter to the Institute confirming that he has bought up all the available yin fen. He asks for Tessa in exchange for the drugs. A series of codes is given below with instructions on to speak to his automaton. A small packet of yin fen is also sent to them as a sign of goodwill. Tessa volunteers to go, while Will and Jem vehemently protest. Jem refuses to allow Tessa to give herself up and throws the small packet of drugs and the letter into the fire grate. Will impulsively throws his hand into the fire and retrieves the medicine. Tessa leaves the hall, overwhelmed. Jem is aghast but consumes the yin fen. Cecily and he sit by Will's side as Charlotte applies salve to his hand. Will and Cecily doze off in the chair itself.
Meanwhile Tessa feels guilty for everything that has happened because of her. Suddenly, she finds Church in the hallway with a message for her; Jem wanted to meet her in the music room. Once there, Jem plays her a song he wrote for her only, and they discuss about how Jem's life was ending quickly and Tessa proposes that they get married the very next day. They begin making out when they are interrupted by a smug Church.
In the living room, Gideon and Gabriel are going through Charlotte's correspondence yet again. They planned to read her letters so that they wouldn't give away anything true in their false ones. Sophie chances upon them, however they show her the meaningless report, and she agrees to help them post it.
That morning, they announce their immediate marriage. Will protests a little, saying that they needed to gain the Clave's approval. Jem in turn, replies that he did not care. A rather insensitive remark from Gabriel turns the discussion into a brawl before they hear the sound of a carriage. Before they reach the entrance of the Institute, Will confesses that his adoration of her had not lessened; it had intensified in the past few months. Tessa is heartbroken to hear that. Will then leaves to call Cyril, at Charlotte's command.
Jessamine is brought back to the Institute being escorted by the Silent Brothers. As the carriage comes to a stop, another one follows, out of which automatons burst out and kill the Gregori. They proceed to attack the Shadowhunters with Mrs. Black. A fight ensues and Mrs Black kidnaps Tessa. By the time Will emerges from the Institute, followed by Bridget and Sophie, Jem is severely injured but bolts after Tessa. Not realizing that Tessa had been kidnapped, Will fights off the automatons. Jessamine, having taken a fatal stab to the back, drags herself over to Will to tells him that Mortmain is in 'Idris', commenting that he is a terrible Welshman, before she dies. Will is stunned when Jem returns and informs him that he had lost Tessa's trail. Jem himself, loses consciousness.
Cecily overhears Will's conversation with Jessamine before she dies and later figures out—by using Jessamine's last words as a clue—that Mortmain is hiding in Cadair Idris, a mountain near where Will used to live in Wales. She asks Gabriel to fetch Will from Jem's side, and she tells him where she believes Mortmain is hiding. Will makes the connection and agrees after which they approach Charlotte.
The Consul, at Charlotte's behest, visits the Institute after the attack and listens to their theory. He refuses to send anyone after Tessa, as neither is there any conclusive proof of her location and nor is she a Nephilim. Gabriel meanwhile is crouched in a corner near the stables and thinking about his brother's injuries. During the battle, Gideon's leg had been severely injured. His blood reminded Gabriel of how he had killed his own father. Josiah, while passing from there, takes advantage of this fact and manipulates Gabriel—making the latter believe that Charlotte's recklessness has caused the damage. Gabriel agrees to properly spy on her.
Will calls Magnus Bane to the Institute to help them find a cure for Jem, who is dying and running out of yin fen. Magnus states that he cannot do anything for Jem, without the drug. He proceeds to ask Will if Jem knows that he is in love with Tessa. Will tells Magnus that he did not want to hurt Jem as it was his own burden to bear. Magnus feels sympathetic and decides to use his magic to an extent, in order to buy Jem some time. He instructs Will to bid a last goodbye to Jem, before leaving to venture out to find Tessa. Magnus retreats to the library. Meanwhile, Jem has been awake all along and inquires about what Magnus was implying when he asked Will if the younger boy loves Tessa.
Will decides to open up, believing that Jem is going to despise him anyways and he begins telling his parabatai about his affection for Tessa; when his curse was cured, he had proposed to her, but she had gently turned him down, stating that she loved Jem and not him. Jem apologizes to Will while the latter insists that none of it was anyone's fault but his own. Jem then implores Will to go after Tessa. With some amount of persuasion, Will finally leaves.
Will goes to the stables to saddle Balios, and is confronted by Cecily. Eventually, she is persistent to go with him, but Will convinces her to stay; if he had to worry about both her and Tessa, the dear would break him. They have a normal conversation, and Will promises that, if he survives and returns, he will visit his parents and tell them the truth about the curse. He gives her the demon-detecting pendant that Magnus gave him, and leaves.
Meanwhile, on the way to Mortmain's lair, Mrs. Black reveals to Tessa that Mortmain resurrected her to serve him again, and has promised her a body that will make her supremely powerful and undetected among the mundanes at the same time. She reveals her automaton body, terrifying Tessa. With no other option left, Tessa throws herself out of the carriage and tumbles down a cliff. Will, who is resting in an inn, has a nightmare and bolts upright, feeling uneasy.
Back at the Institute Will is found missing, and Charlotte forces Cecily to explain what happened. She admits he has gone after Tessa; however she did not stop him for it was with Jem's blessing that he had left. Charlotte takes the charge, and sends a message to the Consul. She then gives each of the London Institute members a task. They all contribute towards finding the cure; Gideon is supposed to go through the books in the library—assisted by Sophie.
Gabriel and Cecily visit Sallows's shop to procure ingredients that Magnus needs to complete the process. They are greeted by Sallows, who is a disdainful satyr, and hands them over the demanded products. He recognizes Gabriel as Benedict Lightwood's son and gives him a parcel that was meant for his father. The contents of the package were severely offensive and in a fit of rage, Gabriel throws Sallows out of the window. While returning home, Cecily is amused with him, but also understands his pain and humiliation at being called out for Benedict's sins.
Magnus, meanwhile, is sent to help Henry with his work, in the crypt. Magnus appreciates Henry's work and together they begin working on Henry's latest invention: the Portal, which can teleport a person from one place to another. Charlotte goes to tend to Jem, all this while.
Tessa is severely injured while falling off the cliff, however before she can pummel to her death, the clockwork angel on her throat grows to a humane size, and assists her in reaching a comparatively safer spot. During her descent, the jade pendant that Jem had gifted her as a bridal gift is wrenched from her throat. Finding no escape. Tessa walks towards a nearby village to seek shelter. While riding through the same area, Will discovers her jade pendant and believes that it is a sign from Tessa. He finds himself feeling hopeful again as he rides further into the night. Tessa feels Will's presence, but believing it is a delusion, finds refuge at a broken hut. Severely injured, she dozes off.
At the Institute, Jem wakes up, shivering severely. Charlotte gives him the last of the yin fen and Jem implores her to stop the search for a cure, stating that "It is over", implying that he was no longer going to survive. When Gabriel and Cecily return from their errand, they find a tear-struck Charlotte informing them of Jem's decision, after which she leaves to call the Silent Brothers. The Brotherhood arrives as Cecily watches them enter from the training room window. She is joined by Gabriel, who doesn't wish to watch Jem's death. Whilst there, she comforts him and tells him that all is not lost, there is still time for him to regain his family's honor. She professes her faith in him, taking him by surprise, when they notice the Silent Brothers leaving.
Will stops at the Green Man Inn for some rest. He writes a letter to Charlotte, informing her of the lead he had found about Tessa—her necklace—and instructed her to bring the Shadowhunters for a battle in Cadair Idris. While having supper, he feels a strange sensation in his body, which turns into agony. He makes his way to the stable and feels the invisible cord in his heart, the one connecting him to Jem, snap and his parabatai rune starts bleeding, signifying that the latter has passed away.
Will is consumed with immense grief, when a pack of werewolves corners him and tries to kill him. They blame the Nephilim race for the spreading of the yin fen drugs. Will fights them and kills most of them, when their pack leader Woolsey Scott commands them to flee. Will is enraged, but Woolsey tells him his own brother's story, and how, despite grieving, he had completed his brother's dream and led the Praetor Lupus. When a dejected Will asks him what he should do, Woolsey advises him to act the way his "brother"—Jem—would have wanted him to.
Will takes a dagger that Jem had once given to him and buries it in the ground, covered with the blood from his parabatai rune, under an oak tree, to eternally mark their friendship. Heartbroken, he decides to continue his journey for Tessa's sake.
Tessa has a dream which indirectly shows her that Will and Jem are in danger. Suddenly an automaton arrives at the hut she is hiding in, and Tessa changes into the woman who once lived in the hut, using the spare blanket she is holding. She is successful in fooling the automatons, until Mrs. Black arrives and recognizes her angel pendant. Tessa is captured and whisked away to their destination.
Charlotte receives Will's missive and writes to the Consul for reinforcements, which he refuses to do. She is approached by Aloysius Starkweather who has a few secrets to reveal, all of them regarding Tessa's lineage. Several decades ago, Aloysius' granddaughter "Adele Starkweather" had passed away during her runing ceremony. However, quite recently, Aloysius had heard Downworlders talk about the revenge they had taken from the Starkweather family. A faerie of the Unseelie Court had revealed that his granddaughter had been abducted and replaced by a similar-looking child. Aloysius' daughter-in-law had once claimed that she was not her own infant, however no one believed her. It was only after the false Adele's death, did they realize that "Adele's" mother's claims were true, however it had been too late. When Aloysius met Tessa, he found a resemblance between his daughter-in-law and her.
He informed her that the faerie, Sallows had been tortured and killed by him, but before that he had warned them that Tessa would be the destruction of the Nephilim. Charlotte immediately writes to the Consul. Gabriel overhears this and writes a letter to the Consul as well, discrediting Charlotte.
Tessa wakes up in a cave in Cadair Idris. She is trapped inside her room by an invisible barrier, and Mortmain appears to speak with her. He tells her the story of her birth. Once her mother, posing as Elizabeth Gray had grown up, she had married a mundane named Richard Gray. One night, he had unleashed an Eidolon—a Greater demon on her mother, who disguised itself as her father. The product of this was Tessa—a half Shadowhunter, half demon. Under other circumstances, Shadowhunters and Demons cannot have children, however, Elizabeth had been an unmarked Nephilim.
Mortmain had then taken Richard under his wing and when Elizabeth felt the effects of carrying a warlock child, he had given her the clockwork angel, which was meant to be a gift from his father to his mother, to protect her, though he never finished it. Mortmain reveals it contains a bit of an angel's soul, and that he finished it, tuned it to her life, and gave it to her mother to keep her safe in the womb. He tells her he intends to use her to breed a new race of half-demonic Shadowhunters.
He then convinces Tessa to Change into John Shade in exchange for yin fen sent as a free gift to Jem. She does as he asks, and Mortmain gets a formula from his father, one that will allow him to bind demon energies to his automatons. Tessa tries to undo the Change but is too late to stop John's soul from writing down the solution. Mortmain sends her back to the room, and finishes binding demons to his machines.
Sophie tells Gabriel that Charlotte needs to speak with him. Gabriel worries she knows what he is doing, but Charlotte just wants to ask if he's okay, and if he needs help dealing with the guilt of killing his father. Gabriel breaks down and Charlotte holds him while he sobs into her shoulder. He realizes the Consul is wrong about Charlotte.
Later, Charlotte receives another letter from the Consul telling her to stop pushing for an attack on Cadair Idris and blatantly refusing to believe her words; also reprimanding her for her incompetence. She is hurt, and can't understand why he is so rude to her. During an argument, Gabriel reveals the contents of the Consul's deal and the threat he had given them of striking off the Lightwood name from Nephilim records. Gideon pleads innocent, stating that they never told Josiah anything incriminating.
Gabriel tells them that it wasn't the end. The night of the attack, he had been manipulated again, and written a letter that dishonored Charlotte, but believing that Charlotte is a righteous leader, does not post it. Gabriel reveals the Consul will never listen to her, and that he asked him to spy on her, though he never sent the letter he wrote. Sophie vouches for both the brothers as well. They all declare their loyalty towards Charlotte as the latter decides to write to the entire Clave, asking them for assistance during this time of crisis.
Everyone agrees to fight with Charlotte, even the servants, and when she questions their ability to defend themselves, Gideon speaks up for Sophie, saying that she has natural talent and would make a fine Shadowhunter someday. He unwittingly blurts out that he intends to marry her, shocking her. Cecily, using her presence of mind, clears the room and her and Gabriel eavesdrop on Gideon proposing to Sophie, an offer which the latter accepts, despite the danger involved in the process of Ascension. Bridget begins singing one of her awful ballads and Sophie excuses herself to "go strangle her".
Cecily, meanwhile, writes a letter to her parents, where she tells them of how Will had finally found a home in the Institute. She goes on to inform them that the Shadowhunter in their blood has accepted this life and they will not be able to return; their rightful place was among their own kind. She thanks her parents for providing her and her siblings a safe future and requests them to remember them. Parallelly, Charlotte releases a message: All the Shadowhunters who believed that the destruction of Mortmain is their priority, should assemble in the Institute, the next afternoon, so as to march to Cadair Idris and end the battle forever.
Tessa is awoken by Mortmain to show her his new automatons, animated by demonic energy. He informs her that he has opened the Pyxis and let loose the demon Armaros. Armaros is now inside the automaton's body, controlling its senses. Mortmain also tells her that his clockwork creatures were capable of independent thinking but deprived of a conscience. He demonstrates the ineffectiveness of runed weapons on them; the blades of Heaven simply turn to ash on touching the creature's body.
Tessa tries to appeal to his better nature, stating that he would have better power over the Shadowhunters by being a constant threat to them, instead of simply attacking. Mortmain punishes her by forcing her to watch the automatons destroy a small Welsh village outside the mountain, effectively proving that he doesn't have a soul like his clockwork army.
Will, wakes up to yelling and destruction. The small inn where he had taken shelter during the night, is nearly destroyed. Getting ready to attack, he finds himself in a precarious position, when he confronts three automatons with a seraph blade. As expected, they do not work on the automatons; however Balios saves Will's life. Will follows the automatons back into the mountain.
Meanwhile in Idris, Inquisitor Whitelaw writes to the Consul to summon all the Shadowhunters across the world for a Council meeting. The urgency of his letter was due to Charlotte's missive regarding their march to Cadair Idris.
Tessa, once again caged in her cave and despairing, tries to destroy her clockwork angel. Without the instrument protecting her, she would be free to die instead of doing Mortmain's bidding. She smashes it with a fireplace poker, but the poker shatters instead and an angel appears before her. It asks her why she wants to destroy her safety. She tells the angel that Mortmain is using her to destroy the Nephilim, something that she couldn't bear to do. The angel tells her that his soul has been trapped in the necklace for years. She apologizes to him, but the angel does not hold her guilty for it. Tessa asks it to let her die, but the angel sadly tells her that it cannot, and disappears. Before it leaves, Tessa asks its name, and the angel tells her: Ithuriel. It also tells her that she is one of the rare people who can claim a guardian angel. Tessa jerks awake, and finds everything in order. She believes that the incident had been a dream and dozes off.
Will eventually makes his way to Mortmain's lair, in the heart of Cadair Idris. He searches and finds a dejected Tessa, and rushes to her without giving a second thought. The invisible barrier cages them both in the room. Will reveals to her that he had felt his parabatai bond bleeding thus proving that Jem is dead. They both grieve his death, which leads to Will confessing his love for Tessa yet again. Uncertain of the future, Tessa asks him to kiss her and they indulge in sexual intercourse that night.
Sometime, during the middle of the night, Tessa wakes up and realizes that her clockwork angel is on Will's shoulder near his neck, and she pulls it away to find that it has left a mark in the shape of a small white star, thus creating the mark of the Herondales that will be seen on the descendants in the future generations.
In London, Henry and Magnus present the Portal to the Shadowhunters. They explain it's working; it will transport the wielder wherever they wished to go, as long as they imagined that place correctly. Despite their reluctance, they have a scarce choice but to try the invention. Charlotte has been fired as the Head, however she no longer cares about her position. They are dejected, as no other Clave member has joined them. Surprisingly though, a few Silent Brothers—Brother Enoch, Brother Micah and Brother Zachariah—join them on their mission. They also inform Charlotte about the emergency Council meeting, due to which, no other Shadowhunter has joined their forces. Cecily is the first one to enter the Portal, which works efficiently, followed by Gabriel and the remaining warriors.
At the Council meeting, Consul Wayland intimates everyone about the situation and demands that they vote for Charlotte's replacement as the Head of the London Institute. However, several Shadowhunters question his claims that state that Charlotte is lying. Charlotte's aunt Callida and the Inquisitor disagree with his decision to ignore her request for help. They are disapproving of the fact that instead of sending an army after her to aid her in the fight, they are busy in fulfilling their political agendas. Aloysius Starkweather openly speaks out against the Consul and supports Charlotte as well.
Tatiana Blackthorn, meanwhile, accuses Charlotte and Will of killing her husband and father. The Inquisitor quickly overrides her declarations, stating that an investigation had been held, where enough proof was found against Benedict Lightwood and Rupert Blackthorn was indeed killed by Tatiana's own father, who had turned into a worm.
The Inquisitor is disgusted by the Consul's dislike of Charlotte due to her gender, and begins arguing with him. The Council Hall is suddenly attacked by a large part of Mortmain's automation army, and the Consul is beheaded before he can reveal why he hates Charlotte so much. Aloysius chuckles hysterically to himself, saying that Charlotte warned them that this will happen, before his throat is crushed by the same automaton that killed the Consul. The Shadowhunters begin fighting, but their weapons are useless against the demonically enhanced machines.
In the cave, Magnus walks in on a partially clothed Will and Tessa and comments about their indulgences. He even finds the star-shaped mark on Will's neck, interesting. Relieved and embarrassed, Will quickly puts on his clothes along with Tessa, and they both follow Magnus to where the others are.
Cecily and the others find a huge room, where several automaton bodies are lying on an elevated platform. Suddenly, an automaton lifts Henry and throws him across the room, effectively rendering him useless. Charlotte meets a similar fate as several other automatons fill in to the room, and a fight ensues.
Will joins in the battle right away, telling Magnus to keep an eye on Tessa. While fighting, Brother Zachariah gets injured, and his hood falls off, revealing that he was, in fact Jem Carstairs. Tessa rushes towards him but is intercepted by Armaros during her journey. Will is stunned but commences fighting with Jem, feeling the thrill of fighting his parabatai for the last time. Magnus uses his magic to help Henry heal, and gathers all the Shadowhunters to make a Portal and escape.
Mortmain emerges from his place and holds Tessa, threatening Will and the other Shadowhunters with her. Tessa implores him to spare them, which he says he shall. He tells her that he plans to keep them as slaves and torture them. He briefs them about the attack on the Council Hall, leaving no doubt in their minds that reinforcements are not going to save them.
A determined Tessa Changes into the angel trapped inside her clockwork angel pendant, Ithuriel, leaving the Shadowhunters in awe as they watch her blaze with fire. The angel protects her as she transforms, her limbs elongating and wings emerging from her back. She speaks in Ithuriel's voice and kills Mortmain, but the heavenly fire of the angel overwhelms her and she Changes back, losing consciousness. Ithuriel's soul escapes her necklace as well.
Tessa is taken back to the Institute infirmary and spends a long time unconscious. She drifts in and out of consciousness as the heavenly fire leaves her body. The Silent Brothers even try runes on her, but they simply sink into her skin like water and fade away. Gabriel finds Cecily by the stables and they have a conversation. Cecily informs him that she chooses to stay in the Shadow World, for that was her true nature; to be a Shadowhunter, and they end up kissing.
The Inquisitor visits the Institute and hands Charlotte a letter from the Council, asking her to be the next Consul. Charlotte does not believe them initially, but then asks for time to think. Will, meanwhile, is sitting by Tessa's bed and she wakes up, delirious and incomprehensive of her surroundings. She mutters about how she has wronged Jem; if it were not for her, Mortmain would never have stolen the yin fen. Will, sick with worry and fear pleads to Charlotte to let Jem visit them one last time, so that he can ease her guilt and sever his ties with her, though the latter was merely an excuse to see Jem.
Gideon advises Sophie to talk to Charlotte, as a friend. Sophie helps Charlotte view herself as a worthy leader and the latter decides to become the Consul on three conditions: one, that she runs the Council from the Institute for the first few years, two, that Will becomes the next Head of the Institute, and three, Jem is summoned from the Silent City to end his engagement to Tessa.
Tessa is awoken by Jem and they have a much awaited conversation. Jem is halfway through becoming a Silent Brother and Tessa confesses that she is glad he survives, though he is no longer her Jem anymore. She confesses her feelings for Will, and Jem gives them his blessing. They come to an agreement—every year, Tessa and Jem will meet on the Blackfriars Bridge for an hour. That one hour of their life will remain a secret, something that wholly belonged to them. Tessa agrees and Jem goes to meet Will. The latter is training in the weapons room; where he had first met Jem when they were twelve years old. Jem comforts his parabatai and tells Will to take care of himself and stating that they will definitely meet again. Tessa later calls Will to her room and removes his apprehension; whatever happened on the night before the war was something she found beautiful and did not repent about either.
Sophie successfully Ascends and becomes a Shadowhunter. The annual Christmas party of the Shadowhunters happens the same day at the London Institute. Tessa reflects on how she had helped Will in recovering from his loss.
She had insisted that Charlotte and the others should not treat him like he is fragile. She sent him to patrol along with Gideon and Gabriel and even though it wasn't like fighting with Jem, Will started feeling more alive . Will had been acting as her guide, showing her all the beauties of London. Once, she snapped when they were visiting the Whispering Gallery, and admits that she wants him to be and act like the Will is he. That night, Will had given her a copy of A Tale of Two Cities with a heartfelt note written inside the title page. Things had been decidedly easier for them since then.
During the party Jem's uncle, Elias, arrives to give Will a sword, Cortana. Elias states that it was supposed to be handed to Jem when he turned of age; now that he could no longer accept gifts, it was fitting that Will receives it instead. Will, however, refuses, after being reminded of his memories of Jem, and escapes outside to sit on the stairs in front of the Institute. Tessa is left to explain to Elias, that Jem was still alive and that using past tense for him had offended Will, who might be recovering, but the grief was never gone. She requests him to keep the sword and pass it down to his own children.
Jessamine visits Will on the steps, now in a ghostly state and tells him that she has been entrusted with the job to protect the Institute. She urges Will to propose to Tessa as she sees that he loves her very much. Magnus visits Will too, and informs him of his imminent departure to New York. Will is dejected to let his friend leave, but Magnus promises to return as well. Tessa eventually finds Will and he proposes marriage to her, an offer which she accepts.
They schedule to marry when Will turns 18, and he uses Henry's Portal to go back to Wales along with Cecily, Tessa, and Gabriel to visit his parents and inform them of the marriage. Will and Cecily have a happy reunion with their parents, and Will announces that Tessa is his fiancee. He also informs his parents about Gabriel, addressing him as a "Lightworm" leaving the latter and Cecily scandalized, while Tessa laughs about.
Tessa and Will get married and have two children, James and Lucie. They had run the London Institute all these past years. It is revealed that Will dies of old age at 78 years old in 1937, and Jem, as Brother Zachariah, visits him on his deathbed and plays to him on his violin for one last time. Tessa is heartbroken when Will dies and begins to travel with Magnus Bane, who understands the grief of outliving loved ones.However, before leaving, Tessa, as per Will's instructions retrieves the dagger he had buried in the ground, when Jem had died—or rather turned to a Silent Brother. She presents it to Jem that year and he tells her to carry it with herself. Magnus and Tessa part ways in New York where they went because of World War II. Church the cat comes with them and is dropped off at the New York Institute.
Later, in 2008, Tessa recalls the pain of watching Will die and leaving her family when she realizes how her children, and grandchildren will age while she remains young. She vows to not get close to her descendants as she doesn't want to cause or bear any pain. Meanwhile, Tessa heads to the Blackfriars Bridge for her annual meeting with Jem and sees that he is no longer a Silent Brother or dependent on yin fen. He tells her that it was "another story of Lightwoods and Herondales and Fairchilds". Despite knowing the agony of losing your loved ones, Tessa determines to take the risk and spend her life with Jem. They reunite and kiss; Tessa invites Jem to travel the world with her, and the wheel comes full circle.
Prologue: York, 1847, and London, 1873
Epilogue: London, Blackfriars Bridge, 2008
- Tessa Gray - the main protagonist of the series, Tessa is a warlock who grew up in the mundane world but has now found a home among the Shadowhunters of the London Institute.
- Magnus Bane - a powerful warlock, Magnus has become a reliable ally to Will, Tessa, and the Shadowhunters of the London Institute.
- Woolsey Scott - Magnus's influential werewolf friend, leader of the London werewolf pack, and founder of the Praetor Lupus.
- Mrs. Black - a follower of the Magister who has faced off against our heroes in the past.
- Will Herondale - a Shadowhunter and ward of the Institute who is driven by his feelings for Tessa and his fierce love and protectiveness of his dying parabatai.
- Jem Carstairs - Will's parabatai and Tessa's fiancé, Jem is determined to make his time with Tessa memorable for her, secretly succumbing to death much faster because of his increased intake of his deadly medicine.
- Charlotte & Henry Branwell - the heads of the London Institute.
- Aloysius Starkweather - the head of the York Institute who makes a discovery about one of our heroes.
- Gideon Lightwood - Benedict's eldest son who is welcomed into the London Institute upon turning his back on his father.
- Gabriel Lightwood - Benedict's son and Gideon's younger brother who is forced to reside at the Institute after a tragedy.
- Cecily Herondale - Will's younger sister who recently came to the London Institute to be trained as a Shadowhunter.
- Axel Mortmain - the wealthy and very influential mundane with a special connection to Tessa's past and has big plans for her future.
- Sophie Collins - the maidservant of the ladies in the London Institute who wishes to become a Shadowhunter.
- The first edition copies of Clockwork Princess came with the genealogical tree of the Carstairs, Herondale, and Lightwood families, thus linking the London Shadowhunters of The Infernal Devices to the Shadowhunters in modern day New York and Los Angeles.
- The original (now hardbound) cover features Tessa Gray holding the Shadowhunter's Codex and wearing the clockwork angel pendant against a backdrop of the Blackfriars Bridge. The repackaged (paperback) cover also features Tessa, this time sitting on the ground, wearing a bloody dress. Her necklace, the one holding her clockwork angel pendant, is on the ground in front of her, while a bigger illustration of the clockwork angel stands behind her.
- The cover model for Tessa on the original and repackaged US covers is Kiersten Brada, who also portrayed Tessa in the trailer. Jem is portrayed by Yoshua "Yoshi" Sudarso and Will by Skyler Hart in the trailer, which was in turn produced by Dirty Robber and directed by Charles Haine.
- The book is told from several points of view, namely: Tessa, Will, Jem, Charlotte, Henry, Sophie, Cecily, Gabriel, Gideon and briefly in Mr. Sallows and Aloysius's.
- In this book, Will gives Tessa a copy of A Tale of Two Cities with a letter that he signs off with "Will Herondale"; in City of Lost Souls, Jace finds the same book, but the inscription ends with his full name, "William Herondale".
- The title seemingly refers to Tessa Gray, who plays the key role in Mortmain's plan to destroy Shadowhunters.
- Clockwork Princess on Amazon.com
- Clockwork Princess blurb — Cassandra Clare's official site
- "Read the full jacket copy for Clockwork Princess" — Cassandra Clare on Tumblr
- Clockwork Princess | Simon & Schuster
- Same models? "Just Tessa," Cassie on Twitter
- Examiner.com - Exclusive interview with Kiersten Brada from 'Clockwork Princess' cover/trailer