After recently joining Zashono Academy, high school student Densuke Mifune accidentally gropes school idol Chiharu Shinonome. As a result, he is forced to join the Eiken club.

It seems every member of the Eiken club is a busty co-ed, and many of the clubs activities involve bikinis. But despite these distractions, Densuke isn't interested in anyone but the shy and beautiful Chiharu.