Nineteen-year-old Aelin Galathynius’ parents were murdered when she was child. Arobynn, an assassin, raised her with the name Aelin Sardothien. Arobynn, aware of Aelin’s identity as the crown princess of Terrasen, stole an amulet from her, unaware that it contains one of the three Wyrdkeys: magical objects that wield tremendous power and can be used to open portals to other worlds.
Years before, Aelin paid off her debt to Arobynn and planned to leave with Sam, the boy she loved. Arobynn had Sam killed and Aelin sent to a slave prison camp. Prince Dorian and Chaol retrieved her and asked her to compete as the king of Adarlan’s Champion.
Aelin left Adarlan and trained in the Fae kingdom with a Fae warrior, Rowan. She finally embraced her identity as the queen of Terrasen. She is ready to reclaim her throne, but first she wants to retrieve the Wyrdkey from Arobynn and extract revenge for Sam’s death.
Aelin returns to the city of Rifthold and quickly finds Arobynn in a tavern. Aelin wants to know how the king controls the Valg, demon creatures from another world who inhabit the bodies of humans. Arobynn makes a deal with Aelin. Aedion, Aelin’s beloved cousin, has been imprisoned for treason and will be executed in three days, during Dorian’s birthday celebration. If Aelin brings him a Valg, he will help to rescue Aedion. Aelin agrees, and Arobynn also tells her where to find Chaol, her former lover.
Aelin meets Chaol and is surprised that he is now a wanted criminal. He tells her how the king arrested Aedion and put a Wyrdstone collar on Dorian, effectively allowing his son to be controlled by the Valg. Aelin is furious with Chaol for leaving Dorian with the king, implying that he is a coward. Chaol is angry that Aelin came back to Rifthold by herself instead of bringing an army to help fight the king. Their reunion ends badly with Aelin returning Chaol’s ring and he returning the Eye of Elena necklace she gave him for protection.
While in Rifthold, Aelin stays at a luxurious apartment she bought years before with money earned from work as an assassin. Arobynn uses one of Aelin’s old rivals, a courtesan named Lysandra, to deliver messages to her. Arobynn hopes Aelin will see Lysandra as a gift and kill her, but instead the women talk.
Lysandra shares information on how Arobynn was involved in Sam’s death. Arobynn also killed Wesley, the man Lysandra loved. The women forge a friendship and form a plan for revenge.
As the time for Aedion’s execution grows near, Chaol asks Aelin to leave Dorian unharmed during the rescue attempt. Having fought the Valg, Aelin believes that Dorian is beyond help and that it would be merciful to kill him. Chaol disagrees, and they argue. Chaol tells Aelin about his belief that the clock tower at the palace is part of a spell and if the tower is destroyed, magic will be restored.
At the palace, Dorian’s body is being controlled by a Valg demon. While Dorian tries to fight it, the demon is winning the fight to control his mind as well.
On execution day, Aelin enters the castle disguised as one of the dancers in a troupe. The dancers, paid by Arobynn, throw a flammable powder on the floor, which ignites and causes chaos. Aelin uses the distraction to free Aedion, and they flee to the castle gardens, only to be stopped by Dorian.
While the demon tries to kill Aelin, she pleads with Dorian to give her a sign that he is still in his body, but getting none, she lifts her sword to kill him. An arrow from Nesryn, Chaol’s friend and former lover, deflects her swing. Aelin and Aedion escape from the castle leaving Dorian alive.
A short time later, Aelin is surprised and overjoyed to find Rowan in Rifthold. While she ordered him to stay away, Rowan has tracked the Fae warrior Lorcan to Rifthold and believes he is after Aelin. Aelin realizes how much she missed Rowan and is now aware of how deep her feelings are for him.
She insists that he sleeps in her bed, which Rowan reluctantly agrees to do. He is sexually attracted to her but doesn’t think it’s appropriate because she is his queen. Rowan uses his Fae senses to tell Aedion that his father is another legendary Fae warrior, Gavriel, and that Lysandra is a shape-shifter stuck in her human form when magic disappeared.
With Aedion free, Arobynn calls in his favor. Aelin and Rowan capture a Valg soldier and take it to Arobynn. The demon tells him that the king puts the Wyrd stone ring on their finger, slices their finger and licks their blood, and then they are bound to him. Arobynn cuts off the demon’s finger, takes the ring and kills him.
Arobynn tells Aelin that he knows she is trying to ruin him by destroying his investments across town. She tells him she will stop when he returns the amulet that he stole from her, and he agrees. After returning the amulet, he gets close enough to slip the ring on her finger, slits her palm and licks her blood. He thinks he controls her. Aelin plays along, knowing that the ring is a fake, planted on the demon after she removed the real one.
As planned, Lysandra kills Arobynn in his sleep. Aelin returns to Arobynn’s home the next day. A banker announces that most of the assets have been left to Aelin. Aelin switched Arobynn’s will a few weeks before. Now she has enough money to build Terrasen’s army.
Before she leaves Rifthold, Aelin must free magic. They go searching in the catacombs beneath the city where a stash of hellfire, a highly explosive liquid, is hidden. They find the hellfire and a temple made of human bones. Scrawled over it are the confessions of sinners.
They also find the ancient king Gavin’s confession that Valg king Erawan wasn’t killed or sent back to his realm, but locked in a tomb in the mountains of Morath, the same place where Duke Perrington and the king are breeding monsters and training witches to fight with wyverns. The Eye of Elena is the key to the tomb.
They hide the hellfire and make plans to destroy the tower. Lorcan finds Aelin, and holding a knife to her throat, tells her that the ring she traded to Fae queen Maeve grants immunity from Valg control to the wearer. He offers to trade the ring for the Wyrdkey. Later, Rowan meets with him and trades the ring for a replica of the amulet.
Before they can carry out their plan to destroy the tower, the group learns that Lysandra has been arrested by the king for being a shapeshifter and is being sent to Morath with the witches for experimentation. They plan to intercept the convoy and rescue her. Aelin, Aedion, Rowan, Chaol and Nesryn gather at the meeting spot in time to see a coven of witches arrive on their wyverns. They are greeted by the king, Dorian and a wagon with Lysandra inside. While the king speaks to the witches, Aelin’s group sneaks Lysandra out of the wagon.
When Dorian sees Manon Blackbeak, the demon inside becomes terrified and temporarily releases its hold on his mind. In a moment of desperation, Dorian flirts brazenly with Manon, hoping that she will kill him for his insolence and put him out of his misery.
Chaol is horrified to see Dorian controlled by the Valg and decides it will be a mercy to kill his friend. Instead of escaping with the others, Chaol tries to kill Dorian, but the witches catch him. Aelin tries to save Chaol and gets into a fight with Manon.
Manon is almost killed by a falling structure but, instead of allowing her to die, Aelin saves her. Manon repays the life debt by leaving messages scrawled all over Rifthold that the human is still inside, a clue that Dorian is still alive. Aelin and Chaol decide to rescue Dorian.
On the morning of the rescue, Aelin pretends to be Celaena, the king’s champion, one last time. She leads Chaol as a prisoner in shackles into the palace. They go into the king’s chambers where both Dorian and his father await them. When Aelin reveals that she has the Eye of Elena, the king orders Dorian to get it, and she runs, forcing him to chase her. Chaol tries to fight the king, who attacks him with dark magic. He leaves Chaol for dead.
Aelin leads Dorian to a glass bridge between two glass towers and lets him get close enough to stab her while she slips the ring on his finger. As Dorian tries to fight the demon inside, Rowan and Aedion detonate the hellfire, destroying the tower and freeing magic. Dorian attacks Aelin with his ice magic, but she defends with her fire magic.
The demon keeps attacking until the king arrives and tells them that he killed Chaol. The grief and anger at his friend’s death pushes Dorian to fight the demon and break the Wyrd collar from his neck. Together Dorian and Aelin combine their powers and fight the king, defeating him.
As the king lay dying, finally freed from the Wyrdstone’s power, he confesses that he did everything to keep Dorian safe from Duke Perrington. When they were younger, they opened the crypt in Morath. Erawen took the duke’s body, while one of Erawen’s minions took the control of the king’s body. The king sensed Dorian’s immense magic when he was born so he built the towers and cast the spell to block magic, keeping Dorian’s secret safe. He tells them that Chaol is injured, but alive, thanks to the Eye of Elena that Aelin slipped into his pocket before the fight.
Dorian kills his father and destroys the glass castle. Aelin uses her fire to melt the glass before it destroys Rifthold, creating a massive glass wall. Rowan uses wind to safely bring Dorian, Chaol and Aelin to the ground.
As Dorian recovers, he struggles with the things he did when he was controlled by the demon. Chaol is paralyzed, but he and Nesryn plan to visit the healers in the southern continent for help. Dorian names Chaol to the position of King’s Hand, and Aelin appoints him as Ambassador for Terrasen, in the hopes that he can convince the southern continent to ally with Adarlan and Terrasen against Queen Maeve and Duke Perrington.
Aelin, Rowan, Aedion and Lysandra leave the castle, and after three weeks of traveling, they reach Terrasen. Aelin Galathynius is finally home.