With the hostile "Abyssal Fleet" constantly threatening the seas, a specialized naval station is built to repel them. Instead of traditional naval weapons, the base is armed with "Kanmusu"—girls who shelter the spirits of Japanese battleships and have the capacity to wear military armor that allows them to harness the tremendous souls inside themselves. Fubuki, a young Destroyer-type Kanmusu, arrives the base as a new recruit; unfortunately for her, despite her inexperience and timidity, she is assigned to the legendary Third Torpedo Squadron and forced into the heat of combat. When she is saved from near-annihilation, the inexperienced battleship vows to become as powerful as the one that saved her.