The following version of this book was used to create the guide: Clare, Cassandra. Chain of Gold. McElderry Books, 2020.

Cassandra Clare's Chain of Gold is divided into 24 chapters, with brief 'interlude' chapters which are flashbacks into the pasts of her various characters. This guide divides the book into six sections, with four concrete chapters each, with the interludes not considered as full chapters.

Chapters 1 - 4 introduce the book's central friend group consisting of James Herondale, Matthew Fairchild, Thomas Lightwood, Christopher Lightwood, and Lucie Herondale. Cordelia Carstairs arrives in London with her family after her father is disgraced, eager to make friends and meet everyone. James experiences traumatic trips into what he calls the shadow realm, a place of darkness and chaos, but he does not yet know what it is. Cordelia is in love with James, but soon after her arrival in London, James' beloved, Grace Blackthorn, appears in London as well. Grace's mother Tatiana seems to be hiding something, though as yet no one knows what. Lucie, meanwhile, meets Jesse Blackthorn, the ghost of Grace's brother, who tells her he senses evil in London. The young Shadowhunters are attacked by demons in daylight -- an unusual occurrence -- leaving several of their peers wounded with no known antidote for the unusual poison.

Chapters 5 - 8, James travels to the shadow realm on purpose to investigate whether the demons attacking him and his friend come from there. He is instead led by a light to Tatiana Blackthorn's house, where Lucie and Cordelia attempt to snoop around. Lucie speaks to Jesse there, who tells her his mother is involved in black magic to try to bring him back to life. Cordelia, meanwhile, investigates the Blackthorns' greenhouse and meets another demon. James appears out of the shadow realm just in time to help her slay the demon, which gives birth to thousands of tiny demons that go unnoticed for the time being. The following day, Cordelia is invited to Anna Lightwood's house, the older sister of Christopher Lightwood. They become fast friends, and Anna invites Cordelia to a Downworlder salon with herself and Matthew, where they plan to ask the warlocks for help in finding a cure to the demon poison slowly killing several of their peers.

In Chapter 9 - 12, Cordelia succeeds in getting a lead relating to the demon poison. The group must speak to Ragnor Fell, a warlock who might know more about it. James and Grace meet up while these developments are taking place, with Grace begging James to help her escape her overbearing and dangerous mother by eloping with her. James says no. He and Grace are attacked by the demons birthed from the one he slew at Tatiana's greenhouse earlier. Soon enough, his friends all arrive to help him. One demon calls James the heir of a Prince of Hell, an especially powerful demon that shapeshifts. James is shocked, and his friends vow to help him uncover the truth. On their way home, Ragnor Fell meets with the group and tells them to search for Emmanuel Gast, a particularly unscrupulous warlock who likely raised the demon whose poison infected their friends. They seek out Gast only to find him dead, yet Lucie is mysteriously able to converse with his ghost, finding out he did indeed raise the demon in question before being murdered by whoever asked him to raise it.

In Chapters 13 - 16, James mourns the end of his relationship with Grace, who has left him after he said he would not elope with her. Tatiana Blackthorn was attacked by a demon and is wounded, but James cannot help Grace because she is now engaged to Charles Fairchild, Matthew's older brother. Christopher breaks the news that some material he collected at Gast's house is from a Pyxis box used to hold demons captive, and that the demon in question is a Mandikhor demon. James, Matthew, Cordelia, and Anna go back to the Downworlder artistic salon to steal a Pyxis box they know Hypatia Vex, a warlock there, owns. At the salon, Cordelia performs a dance to distract the crowd from Anna, who seduces Hypatia and gets the box. James and Cordelia finds themselves alone in a room for a moment, and begin kissing to prevent intruders from wondering about two Shadowhunters being in Downworlder territory. Matthew catches them, and James explains it was only a game, while Cordelia looks on and wonders if he felt anything for her the way she did for him. The next day, James and his friends enlist the help of famed warlock Magnus Bane to try to trap the Mandikhor demon, but the plan goes awry as Cordelia is almost killed. Lucie raises the dead to help save her friend.

Chapters 17 - 20 describe Cordelia's painful discovery that her father's disgrace is due to his alcoholism, a fact hidden from her by her family until now. Lucie, on the other hand, feels better than ever, having found out that she has the power to command the dead and thus is mysteriously connected to ghosts in a way she does not understand yet. Then, Christopher is injured in a demon attack on his house, just as he was about to finish the antidote to the demon poison. Instead, Thomas and Lucie must try to find the root he needs at the Blackthorns' mansion. James, Matthew, and Cordelia head to the Silent City, where the wounded -- including Christopher -- are kept. They watch the wounded become possessed and speak to James, urging him to attend a meeting with a demon. Outside the Silent City, an archway into the shadow realm stands ready for James. He steps into it despite his friends' protests and meets his grandfather, Belial, a Prince of Hell. Belial asks to use James' body to gain more power, but James refuses. Belial raises the Mandikhor demon, but Cordelia quickly jumps through the archway to join James, and together they defeat the demon and wound Belial enough to keep him powerless for a while. Lucie and Thomas have gotten a hold of the root, completed the antidote, and take it to the Silent City to help heal the wounded. James is badly injured and nearly dies, but Jesse gives up his last living breath -- trapped in a locket around his neck -- to James to help him survive. Jesse begins to fade away.

In Chapters 21 - 24, James wakes up at his home after the meeting with his grandfather. Grace visits him, clamps a bracelet proclaiming loyalty forcibly onto his wrist, and watches as he once more succumbs to her charms and is in love with her. Cordelia is hurt when she hears he loves Grace again, not knowing that there may be an inorganic reason for it. James announces he must go to the Blackthorns' house in Idris, the Shadowhunter country, to kill an automaton which Grace's mother, Tatiana, has imbued with black magic in order to kill all Shadowhunters. He does so, burning down the house entirely. At the next Enclave meeting, Tatiana accuses him of committing arson, and Cordelia tries to defend James by claiming he spent the night with her in her room and thus could not have done so. She is instantly branded as an unmarriageable woman, until James proposes to her on the spot to save her reputation. He tells her privately that they can be married for a year to save her reputation, then divorce amicably and both have a chance at real love. Cordelia is hurt because she really does love James, but she sees he does not feel that way about her. At their engagement party, they dance and she feels almost excited for their year ahead of living together as man and wife.