The following version of this book was used to create the guide: Clare, Cassandra. Chain of Iron. McElderry Books, 2021.

In Chapters 1 – 6 of Chain of Iron, James Herondale and Cordelia Carstairs get married to preserve the reputations of their families, with only their friends knowing the wedding is a sham. As the pair get to know each other as partners, Cordelia’s father returns from his retreat at the sanatorium but still battles his alcohol addiction. Meanwhile, Lucie and Grace Blackthorn try to bring Jesse back from the dead and tell no one of their efforts. Next, in Chapters 7 – 12, a series of murders in the Shadowhunter community have everyone shaken. When Cordelia’s father is the latest victim, James and the Merry Thieves decide to investigate for themselves but clash with Thomas, who insists that he is brave enough and strong enough to patrol London on his own, heedless of any danger.

In Chapters 13 – 18, Thomas is caught at the scene of yet another murder and is blamed for the string of attacks. While Alastair tries to prove his innocence, the Merry Thieves uncover the tool used to murder the Shadowhunters and seek to find out more about its powers and who is using it. They visit a Shadow Market together, with Cordelia and Matthew spending time together much to James’ bewilderment and annoyance. Later, in Chapters 19 – 24, the gang discovers that the tool used to commit the murders is able to remove and transfer Shadowhunter runes. James has an inkling that the killer is none other than his grandfather, Belial, a demon. With the help of Magnus Bane, a warlock, James and Cordelia travel to Belial’s realm to confront him, only to have him escape them. Back in London, they realize that Belial is controlling Jesse Blackthorn’s body and prepare for a fight with the demon.

In Chapters 25 – Epilogue, James and Cordelia discover that Cordelia, instead of swearing her allegiance to the smith who crafted her sword, as she thought she had done, has actually sworn allegiance to Lilith, an enemy of Belial’s. Cordelia manages to wound Belial after Lucie commands Jesse to expel the demon from his body successfully. Belial disappears, but the friends must then deal with the emotional aftermath. When Grace visits James and tries to reconcile with him, Cordelia misunderstands the situation and rushes off to see Matthew, who convinces her to go to Paris with him. By the time James has discovered that Cordelia is missing, he is too late to confess his newfound love for her and must watch her leave.