Orenchi no Furo Jijou

Tatsumi lives alone until he helps Wakasa, a merman in need of shelter. His unexpected guest takes up residence in the bathtub, leaving the quiet teenager to adjust to a cheerful and demanding roommate.

Visits from Wakasa's other aquatic friends make the small household even less ordinary. Managing food, bathwater, and limited space becomes part of their routine, while the contrast between Tatsumi's calm practicality and Wakasa's exuberance gradually develops into an unusual friendship.