Rounin student Manji lives alone in an apartment without a bath. One day, his sister-in-law Harumi runs away from home and suddenly shows up at Manji's place. Harumi used to be a regular at a local public bathhouse and was close with the owner, Sasagi. Ignoring Manji's surprise, Harumi decides to head straight to the bathhouse. She convinces Sasagi to let her bathe before opening hours and joyfully indulges in the long-missed experience. However, she overheats and becomes too dizzy to move. Manji rushes to help, but just then, female customers begin arriving, quickly turning the situation complicated.