Zashono Academy is a massive school with over 5000 students. Densuke has so many choices when it comes to extra-curricular activities that he can scarcely chose one-until he finds out about the mysterious Eiken club. The group's activities and membership are shrouded in mystery but now, Densuke is about to find out first hand what Eiken club is all about, and why all the rest of its members are cute, busty girls. Densuke is surrounded by beautiful women, but all he wants are the affections of a girl named Chiharu. Will he ever make his way through the water slides and yogurt fights so that he can finally talk to her?