Aboard Prince-Captain Rashad's urgan, Arkold wakes from a nightmare, to find that the urgan is partially flooded, and that Sirens are boarding and attacking the crew. He tries to rescue a maimed comrade, but a Siren slays him. Arkold and a couple of other legionnaires fight off Sirens, and then Arkold climbs into a gunnery chair and tries to fend off the attackers. He learns that a large creature known as a juggernautilis is coming to attack the ship. He uses a daring plan to try to knock some exploding sea life into the approaching juggernautilis, and to steer it into a school of the creatures. The plan works, and the attack is averted.