Feyre watches the battle open with the Bone Carver, the Weaver, and Bryaxis crashing into Hybern’s ranks and causing immediate devastation. Rhys follows by blasting a huge section of the enemy into mist, Azriel strikes the exposed flank, and the Illyrians dive in on Rhys’s signal. Hybern adapts quickly, however, by unleashing winged creatures and faebane-tipped arrows that pierce magical shields, so the fighting turns deadly even as Tarquin, Helion, Kallias, and the Night Court press forward.

As the front lines collide, Feyre keeps mental control over Bryaxis and the Bone Carver so they attack only Hybern. Rhys judges that the battle is still undecided and says Hybern’s attention must be pulled elsewhere before he joins the field himself. At that moment, a horn sounds from the north and three new forces appear: Beron’s army, the remnants of the Spring Court, and a human army carrying Graysen’s crest, led by Jurian.

Eris arrives on the knoll and reveals that Tamlin forced Beron to come. He says Tamlin and Jurian want orders, while Beron’s sons move through Hybern’s host destroying wagons full of faebane with blue fire. Realizing the surprise reinforcements have created the distraction they needed, Rhys sends Feyre, Amren, Nesta, and Elain to move quietly toward the Cauldron behind enemy lines, following the bloody path the Weaver is cutting toward it.

As they start down the hill, Nesta suddenly collapses and Rhys instantly understands why: Hybern is waking the Cauldron. Rhys and Azriel throw up massive shields over their army while Nesta, overwhelmed by what she senses, begins screaming Cassian’s name. Cassian breaks away from the Illyrian ranks and flies toward them, pulled off the exact point where the Cauldron’s strike is about to land.

The Cauldron fires a blast of white destruction from Hybern’s rocky position, tearing through Azriel’s shield, then Rhys’s, then the Illyrians’ own defenses. Thousands of soldiers are reduced to ash, and Feyre realizes Nesta’s warning saved Cassian from being at the center of the blast. Hybern fires again into its own lines to kill the Bone Carver, and despite a strange final look and smile, the Cauldron obliterates him completely.