A woman in the midst of an unpleasant divorce moves to an eerie apartment building with her young daughter. The ceiling of their apartment has a dark and active leak.

Kaori (Riko Narumi) is a intense kendo fighter who has been training since she was young. Sanae (Kie Kitano) is a girl who has only participated in kendo casually, but somehow manages to beat Kaori in the final tournament of junior high school. Although Sanae doesn’t particularly care about it, Kaori holds a grudge, setting up a rivalry that bleeds over into high school.