Aedion’s diminished army reaches Perranth, a dark-stoned city beside the frozen Lanis River. Because Perranth’s walls were destroyed by Adarlan and never rebuilt, Aedion chooses the fields beyond the city for a stand, hoping the frozen river will give Terrasen its only advantage against Morath’s larger force.

During the brief delay bought by the Whitethorn royals’ fading shields, Aedion sends Nox Owen into Perranth to seek reinforcements. Nox returns with only a few hundred poorly trained volunteers, some old weapons, food, blankets, and nonmagical healers. Rumors spread that Aelin has abandoned the army, and although Aedion shuts down the talk, Aedion privately wonders whether Aelin should have used the Wyrdkeys as weapons rather than pursue the Lock.

When Morath arrives, Aedion rides the lines and joins the Bane in beating sword against shield. The sound rallies the army but also conceals the cracking of the river ice. Aedion reflects that the battered shield he carries belonged to Rhoe Galathynius, Aelin’s father, and sees it as a symbol of everything Aedion has sworn to defend.

Morath begins crossing the frozen Lanis. At the right moment, Endymion and Sellene use the last of their power to tear the ice apart, plunging soldiers into the freezing water. Ren Allsbrook’s archers shoot down ilken that try to rescue the drowning troops, but the trap kills only about two thousand enemies before the Fae royals’ magic breaks and the Valg princes freeze the river again.

Morath advances across the new ice, ignoring trapped soldiers beneath it, and Aedion charges as the battle begins in earnest. Lysandra, fighting in a wyvern’s form, realizes the ilken have prepared an ambush for her, so she draws them within range of Ren’s archers and kills them after they are grounded.

Lysandra shifts into a ghost leopard and tears into Morath’s foot soldiers, but Terrasen’s lines buckle under overwhelming numbers. Ilken devastate the cavalry, soldiers begin fleeing, and Morath punches through the center. With the lines collapsing and no one left behind Lysandra to finish fallen enemies, Lysandra concludes the battle is nearly lost and looks toward the ilken on the right flank, deciding she must act.