Chapter Fifty-Four

Cassian and Nesta confront Lanthys in his cell after the Harp accidentally releases him when she commands it to open the Prison's wards. After Cassian is beaten down, Nesta discovers her Made sword Ataraxia can harm the supposedly unkillable creature. She defeats Lanthys with the blade and Cassian's help, then uses the Harp to transport them both to safety in Velaris—but Cassian collapses from his injuries upon arrival.

Cassian and Nesta enter Lanthys's open cell, where the ancient, immortal creature emerges from mist. Cassian realizes that when Nesta commanded the Harp to release her from its power, it simultaneously opened Lanthys's cell as well. Lanthys reveals he can sense the Harp and understands its immense power over seasons, kingdoms, time, and worlds—particularly its final string, which even Death obeys. When Lanthys begins to discern what Nesta is, Cassian attacks and orders her to run, giving her his Siphon. Nesta flees upward but realizes she cannot abandon Cassian. Recalling the Harp's mention of moving through space and its connection to twenty-six dimensions, she plucks one of its strings and transports herself back down to Cassian's side. However, Autumn Court soldiers sent by Briallyn and Koschei are descending the Prison's path. Lanthys hurls both Cassian and Nesta into the rock walls. When Cassian is knocked unconscious, Nesta stands alone between him and Lanthys. She draws her sword Ataraxia, which blazes with silver light—causing Lanthys to transform from mist into a golden-haired male form, shocked that her blade affects him. Lanthys attempts to seduce Nesta with visions of dark thrones, palaces, and intimate union, but she sees through his illusions, recognizing his greed and his intention to control her. As Lanthys approaches, Cassian regains consciousness and hurls a dagger into his chest while Nesta attacks with Ataraxia, slicing him apart despite his supposed immortality. His death sends shockwaves through the Prison, causing inmates to scream and pound their cell walls in fear. Nesta picks up the Harp and uses it to transport both herself and the badly wounded Cassian to Feyre's house in Velaris using three strings. They arrive safely, but Cassian immediately collapses on the grass.