As Duke Constans's galley remains locked into their ship and Eudoxia's warped sea-soldiers board through smoke and confusion, Alex freezes at the sight of a fish-like woman attacker. Sunny quickly decides the only available escape is upward, and despite Alex's terror of heights and inability to swim, Alex follows Sunny into the rigging because the deck is closing in with enemies.

On the aftcastle, Brother Diaz narrowly avoids a fish-man's hooked weapon, falls over the side of the raised deck, and survives only because he lands on the lower deck instead of in the sea. Before he can be killed, Vigga crashes in and saves him, then tears through several attackers with brutal efficiency. Brother Diaz, terrified but useful, spots threats through the smoke and shouts warnings that help Vigga kill more boarders, including a grotesque tentacled creature.

Elsewhere, Balthazar and Baptiste retreat belowdecks to escape the fighting, only to find the hold flooding around the galley's ram where it pierced the hull. As they look for a way out, a long-limbed sorcerer emerges from the shadows and reveals that he has been sent to kill Balthazar. He is a phrenomancer, and he proves it by pinning a control-rune to Baptiste's forehead and forcing her to speak in unison with him and turn on Balthazar.

Higher in the rigging, Alex and Sunny reach a yard above the deck and realize the ship is definitely sinking. Alex sees Constans below directing the attack, while more hybrid sea-creatures climb after them, including a crab-like boarder. Sunny hides on the far side of the ratlines, lets the crab-man pass, steals his dagger, and stabs him from behind, but he keeps climbing, forcing the two girls to scramble higher.

Back on the aftcastle, Jakob kills a fish-woman and pauses long enough to recognize that even these monstrous soldiers were once people, then braces himself as Constans personally boards. Constans casually discusses his mother's experiments, his brother Marcian's militarism, and the theatrical appeal of their confrontation before challenging Jakob to a duel on the burning, listing ship. At nearly the same time, Sunny knocks a whale-oil lantern into the falling crab-man while trying to stop him, and the lantern drops toward the fire below, threatening to make the already desperate battle even worse.