Camilla attacks Cytherea before the Lyctor can finish Gideon, forcing Cytherea back with furious knife work until Cytherea catches Camilla in bone and begins draining her. Harrow arrives with a mass of skeletons, gives Gideon her two-handed sword, and buries Cytherea under bone. Cytherea breaks free and summons the huge regenerating bone construct that killed Isaac, forcing Gideon and Harrow into their first true fight as cavalier and necromancer.

Harrow identifies that a necromancer alone cannot defeat the construct, but Gideon can help her. Gideon carves openings where Harrow directs her through a mental link, and Harrow uses skeletons melted into hot bone matter to seal the creature’s legs with perpetual bone. The tactic works long enough to immobilize the construct, but Gideon is thrown, Harrow exhausts herself, and Camilla confronts Cytherea directly.

Camilla nearly pins Cytherea with a knife, but Cytherea wounds and traps her. Ianthe then appears and stabs Cytherea, beginning a Lyctor duel that drives the combat out onto the terrace. Ianthe wounds Cytherea badly, and Palamedes’s hidden damage reopens because Cytherea had only covered it over, not healed it; however, Cytherea outlasts Ianthe, siphons her power to heal, and cuts off Ianthe’s arm.

Camilla wounds Cytherea in a hidden swelling near the shoulder, but Cytherea drains Ianthe again to repair the injury and turns on Gideon, Harrow, and Camilla. Gideon challenges Cytherea with her two-hander, but even Gideon’s best strike cannot cut through the Lyctor’s body. Harrow rises despite near-collapse, summons perpetual-bone giants, and then shields Gideon, Camilla, and herself inside a thick bone shell when Cytherea’s damaged but still lethal construct breaks free and attacks.

Inside the shelter, Harrow proposes launching Gideon and Camilla through the wall toward the sea while Harrow stays behind to distract Cytherea. Gideon refuses, Camilla also offers herself as a distraction, and all three realize they have no workable escape. Gideon forgives Harrow, confesses that Harrow matters more to her than the Locked Tomb or duty, and Harrow names Gideon the greatest cavalier the Ninth House has produced.

Gideon then understands what her role must be. She tells Harrow that there is no Gideon without Harrow and invokes the cavalier vow, one flesh, one end. Before Harrow can stop her, Gideon turns away and falls forward onto the iron spikes, sacrificing herself so Harrow can survive and know what to do next.