Feyre prepares for the mission to Hybern by arming herself with hidden blades and carrying both halves of the Book of Breathings. In the townhouse foyer, Amren warns Rhys not to linger near the King of Hybern and tells Feyre to abandon the attempt if the spell fails or the Cauldron cannot be moved. Rhys says goodbye with visible reluctance, and Cassian and Azriel vow to protect Feyre with their lives before Mor takes Feyre for the first leg of the journey.

The group travels by winnowing and flight to Hybern. Cassian catches Feyre in midair as they approach the island, and Feyre feels the land as ancient, empty, and hostile. Cassian points out the King of Hybern's cliffside castle and explains that Mor has timed their entry to a guard shift and opened a small sea door that leads closest to the lower levels.

At the entrance, Azriel scouts ahead and silently confirms that he has already killed the guards. Inside the castle, Feyre does not need directions because the Cauldron pulls at her constantly, while the Book of Breathings whispers of home. As they move through dark corridors and down into the dungeons, Cassian and Azriel repeatedly split off to eliminate more guards, showing how carefully the raid has been planned.

During the descent, Feyre realizes Mor's true role is to get her out if Cassian and Azriel fall. Driven by anger over Hybern's attack on Velaris and its past cruelty to Rhys, Feyre follows the Cauldron's pull deeper underground. At last, after one final staircase, the group enters a round chamber beneath the castle and finds the Cauldron waiting on a dais at its center.