The alien Abyssal Fleet keeps threatening humanity, and the Kanmusu—girls who embody the spirits of Japanese warships—stand as mankind's final safeguard. Their relentless battles almost ensure that the Kanmusu will sink beneath the waves into oblivion, and the Mutsuki‑class destroyer Kisaragi is among those doomed vessels.
After a successful nocturnal raid, the Eighth Fleet"s Kanmusu spot Kisaragi alive yet unconscious drifting at sea level. This odd circumstance and the destroyer"s bizarre conduct make the Kanmusu wary of her. Moreover, other ships begin to hear uncanny voices and encounter crimson waters that corrode their gear; strangely, Fubuki, the flagship of the Fubuki‑class destroyers, remains unscathed.
As Fubuki and her comrades confront these strange phenomena, the grim truth of their existence and the Abyssal Fleet"s menace slowly unravels. Still, the girls must press onward to free the ocean and safeguard those they love most. In the face of relentless darkness, their resolve remains unbroken for the future of humanity and hope.
