- The book will take place about a week after the events of Chain of Iron.
- Some key word clues Cassie has given on the book are: "Paris, kidnapping, Cornwall, a party where a terrible thing happens, death, inventions, science, secrets revealed, a new Shadowhunter arrives in London."
- The book will open with Matthew and Cordelia in Paris.
- The reason why Lucie flinched while practicing her and Cordelia's parabatai ritual will be revealed.
- There will be an unexpected romantic scene.
- Matthew wants to tell people his secret; especially his parents and James.
- Matthew will explain his personal financial situation.
- Ariadne will pick a new name for herself by the end of the book.
- We will see new places.
- There will be consequences for the way Lucie raised Jesse though it was not entirely necromancy.
- Blackthorn sword has a name that will be revealed.
The word echoed in Cordelia’s ears. Though she had clambered blindly into a fiacre with Matthew, though they were rattling quickly through some part of Paris, she still felt as if she were standing in front of the cabaret, hearing the guard refuse her entrance. I know what I know. You cannot come inside.
Because you are corrupted within, said a small voice inside her. Because you belong to Lilith, Mother of Demons. Because of your own foolishness, you are cursed. No one should be around you.
“Daisy?” Matthew’s worried voice seemed to come from far away. “Daisy, please. Talk to me.”
“Regardless,” said Matthew, “I’m glad to hear that you’ve returned to your usual busy schedule of ruining London’s women for London’s men. Before I left for Paris the buzz was that you had gone entirely out of circulation.”
“Oh really?” said Anna.
“It was all anyone seemed to want to talk about at the Ruelle,” Matthew pressed. “Mundane, Downworlders, all the ladies remaining completely unseduced, and not happy about it.”
“I can hardly seduce everyone,” Anna shrugged. “Some of them will just have to seduce one another.”
Now it was Matthew’s turn to raise an eyebrow. “I’m not worried about them,” he said. “I’m worried about you.” In a lower voice he said, “I heard about Ariadne.”
James took a deep breath. “Daisy,” he said. “I wanted to say — I never apologized.”
She turned, laid the striped dress on the bed. Stayed there, fiddling with its buttons. “For what?”
James wasn’t sure how he’d expected Lucie to respond to their arrival, but he was startled nonetheless at the fear that flashed across her face.
She took a step back, nearly knocking into the boy standing next to her — Jesse Blackthorn, it was Jesse Blackthorn — and flung her hands up, as if to ward them off. As if to ward off James, and her father.
- Cassie plans on the special content for this book to be the story of the found family tree with explanations as to why it is incorrect and what the true family tree is.
- The book was initially intended to release in March 2022 like its predecessors but was pushed back several months to November as a result of Covid-19 delays.
- "Around a week [will pass between CoI and CoT]." Cassandra Clare on Tumblr
- "A short amount of time has passed — no more than a week." CC on Tumblr
- Summary of Cassandra Clare's UK tour date for Chain of Iron
- TMI Source live recap
- TMI Source's 10 year anniversary chat with Cassandra Clare
- "[Matthew] does have plenty of money from Charlotte and Henry, which has been paid to him in the form of an allowance for years" & "he has some extra money that was willed to him by grandparents." Cassandra Clare on Tumblr
- "Ariadne decides for herself what she wants to be called, and it is neither Ariadne nor Kamala." Cassandra Clare on Tumblr
- "Yes, we will see new places, like Paris." CC on Tumblr
- "Chain of Thorns is a long book, and the characters go to many places." CC on Tumblr
- "We’ll have to wait to see what the consequences of that are." CC on Tumblr
- Cassandra Clare on Instagram Live
- "I decided [the extra for Chain of Thorns is] going to be the story of the family tree, what it actually is and why there was a messed-up version of it." Cassandra Clare on Tumblr
- "There is an explanation of why the family tree ended up the way it did; that’s special content in the first edition of Chain of Thorns. But a new family tree is not." CC on Tumblr
- "CoT in 2022. All March." CC on Tumblr
- "It's likely that because of delays in the publication process due to COVID, the last TLH book and Sword Catcher will publish later than originally anticipated." Cassandra Clare on Tumblr