A New Beginning, A Lingering Unease
Sixteen-year-old Clary Fray trains to be a Shadowhunter, embracing her powers. She is with Jace Herondale, and her mother, Jocelyn Fray, plans her wedding to Luke Garroway. The world seems peaceful after the Mortal War. But this peace does not last. Shadowhunters are murdered, their bodies found in faerie lands. This sparks new tension between Shadowhunters and Downworlders, threatening to restart the conflict. Clary is caught between her desire for a normal life and the growing threats.
Simon's Unveiling and the Mark of Cain
Clary's friend, Simon Lewis, faces his own problems. His mother, Elaine Lewis, finds out he is a vampire when she sees him feeding. Horrified, she throws him out, leaving Simon homeless and heartbroken. Simon still has the Mark of Cain, a powerful protective symbol from the angel Raziel. This mark makes him invincible but also makes others wary, as anyone who tries to hurt him will suffer sevenfold. This mark becomes important throughout the story.
Jace's Disturbing Visions and Growing Distance
Jace Herondale, Clary's boyfriend, starts acting strangely. He becomes distant, pushing Clary away, which confuses and upsets her. He refuses to explain, making Clary feel hurt and alone. Unknown to Clary, Jace is tormented by nightmares and visions. These visions often show him harming Clary, his friends, or himself. He fears he is losing his mind and becoming like his father, Valentine Morgenstern. He tries to protect Clary by keeping her away.
The Rise of the Cult and the Resurrected
As Shadowhunter murders continue, a pattern appears. The victims are not just dead; they are resurrected as grotesque, soulless demons called 'forsaken.' These forsaken are used for more violence. A powerful, dark force is at work, and a cult dedicated to Valentine Morgenstern, Jace and Clary's deceased father, is suspected. This cult wants to resurrect Valentine and continue his war against Downworlders and possibly the Clave.
Maia's Brother and the Lycanthrope Clashes
The discovery that murdered Shadowhunters rise as forsaken affects Maia Roberts, a werewolf in Luke's pack and Simon's friend. Her brother, a Shadowhunter, is one of the victims turned into a demon. This tragedy fuels Maia's anger, increasing tension between werewolves and Shadowhunters. It also puts pressure on Luke, as pack leader, to find answers and protect his own, complicating Downworlder politics.
Raphael's Offer and Simon's Sanctuary
With no home, Simon is vulnerable. Raphael Santiago, leader of the New York vampire clan, offers Simon shelter in the Hotel DuMort. While it seems kind, Raphael's motives are rarely simple. He sees potential in Simon, especially because of the Mark of Cain, and wants to influence him. Simon, desperate for a place to belong, accepts. But he soon realizes living among vampires brings its own dangers and political games, especially as Raphael tries to use Simon's abilities.
Jace's Confession and the Angelic Influence
Upset by Jace's continued distance, Clary confronts him. Jace, at his breaking point, confesses the visions he's had – visions of him killing Clary, Alec, Isabelle, and himself. This revelation disturbs Clary, and they seek answers. They consult Brother Zachariah, a Silent Brother, who says Jace's visions are caused by a dark angelic influence. The angel Ithuriel, corrupted by Valentine, had a connection to Jace. Now, a similar malevolent angelic force tries to control him, stemming from the demon Lilith's blood.
The Arrival of Lilith
The true enemy is Lilith, the Greater Demon and mother of all demons. She orchestrates the Shadowhunter murders and their resurrection as forsaken. Lilith wants to bring back Sebastian Morgenstern, Clary's brother and Valentine's son, who died in the previous book. She needs a powerful vessel for Sebastian's return. She has been manipulating Jace through his dreams, trying to corrupt him and prepare him to host Sebastian's soul. Her influence is the source of Jace's torment and dark impulses.
Simon's Abduction and the Ritual
Lilith, seeing the unique properties of Simon's blood – his ability to walk in daylight as a Daylighter vampire and his angelic Mark of Cain – targets him for her ritual. She abducts Simon, intending to use his blood as a key part of Sebastian's resurrection. Simon's angelic protection makes him a powerful conduit, and Lilith believes his blood will anchor Sebastian's soul. This abduction starts a desperate race for Clary, Jace, and their friends to rescue Simon and prevent Sebastian's return.
The Battle at the Ceremony Site
Clary, Jace, Alec, Isabelle, and Luke track Lilith to an abandoned church where she performs the resurrection ritual. They arrive to find Simon bound and Lilith preparing to finish her magic, with Jace heavily influenced and almost her puppet. A fierce battle begins against Lilith and her demons. Clary, using her rune-creating abilities, fights to save Jace and Simon. The Mark of Cain on Simon proves to be a powerful weapon, retaliating against Lilith when she tries to harm him, weakening her.
Sebastian's Return and Jace's Sacrifice
In a final moment, Sebastian Morgenstern is resurrected. But the ritual is not fully successful. Jace, trying to save Clary and stop Lilith, sacrifices himself. He is consumed by the dark fire that brings Sebastian back. Instead of being destroyed, Jace becomes linked to Sebastian. They are now bound, sharing a life force and a connection Clary cannot break. Lilith is defeated, but at a cost: Jace is now a dark version of himself, a puppet of Sebastian. Clary is left devastated by this loss and the return of her evil brother.