Ashiya Souma has been taking swimming lessons at a local swimming school since he became an adult. One reason is that he likes swimming, but another reason is that he gets to see girls in swimsuits!

And in the summer, there are more girls with clear suntan marks on their bodies. Harumi Tose is a junior student whom Souma have taken care of since his school days, and he miss her a lot.

When he meets her again after a long time at a swimming class, he is surprised to see how much her body has grown at once. Whether he's swimming or resting, he just can't take his eyes off her.

All of sudden, his junior confesses to him. Will the things he has been fantasizing about become a reality?

[From official site]