Amren appears in Feyre’s room at dawn and bluntly remarks on Feyre’s nightly vomiting before tossing her a gold amulet. Amren says the amulet once got her out of the Prison and will keep Feyre from being trapped there, but only as a loan. That gift gives Feyre enough courage to go with Rhys to the Prison after failing the day before.

As Feyre and Rhys climb the mountain, Rhys warns her that the prisoners can listen through the rock, so she must be careful what she says. Their conversation turns to his inner circle: Rhys says Cassian is the best warrior he knows, explains that Azriel’s scarred hands came from childhood torture by his half-brothers, and describes Mor as the power he would call on if all his armies failed. Rhys also reveals that Amren is something far more dangerous than an ordinary faerie and that, in a final catastrophe, he would rather unleash her on the world than let the enemy win.

Inside the Prison, Feyre fights panic as Rhys guides her through the silence and darkness. Rhys explains that the Prison is effectively its own ancient power, that his blood opens its gates, and that its inmates cannot be released once they are sentenced there. During the long descent, Feyre learns that Amren was imprisoned there for millennia, likely came from another world, and may be one of several beings trapped in Prythian from elsewhere.

At the bottom, Rhys opens the Bone Carver’s cell and offers him the bone that killed the Middengard Wyrm. The Bone Carver appears to Feyre as a dark-haired boy and demands answers about what she experienced when she died. Following Rhys’s instructions, Feyre tells the truth: she heard her neck break, existed briefly as a spirit bound to Rhys through their bargain, and chose to return because she wanted to go home. In return, the Bone Carver says Jurian could only be remade if his soul was preserved and the Cauldron was used, then explains that the Cauldron is an ancient source of creation magic whose missing feet were hidden in three temples that have now been ransacked.

When Feyre presses further, the Bone Carver all but confirms that the King of Hybern has the Cauldron and may use it to shatter the Wall after testing it on Jurian. Feyre, pushed into deeper honesty, admits that after killing the two faeries Under the Mountain she intended to kill herself if she survived, a confession that visibly devastates Rhys. The Bone Carver then reveals the only likely countermeasure: reunite the two halves of the Book of Breathings, one held by the Summer Court and one by the mortal queens, because its spells may nullify or control the Cauldron. As Feyre and Rhys leave, the Bone Carver says he will one day carve Feyre’s death; afterward, Feyre learns that while she saw a strange child, Rhys saw Jurian.