Tatsumi and Wakasa both have a bubble bath together, but when the bubbles dissapear and Wakasa decides to make them on his own, things don't end up too well.
Tatsumi is a high school boy who lives by himself. One day, a devastatingly handsome merman named Wakasa moves into the bathtub in Tatsumi's home. Wakasa is a bit self-centered but cute, while Tatsumi is cool but a busybody.