Kagerou is a shipgirl stationed in Yokosuka Naval Base. As the nameship of the Kagerou class, she pushed herself to do her best in training, but things didn’t go very well. In fact, she was put to form a fleet consisting of Ushio, Arare, Satsuki, Nagatsuki, and Akebono— the leftover shipgirls that were unable to join any fleet because of their respective reasons! Kagerou, with her stationing delayed and getting in last out of all of them, found herself stuck in such a fleet and thus, her unpredictable daily life in Yokosuka Naval Base began.