Shimeru Futaba is a fairly ordinary guy who likes his friend Misaki. Futaba is also a member of the wrestling club. One day during recess, his fellow club members give him an erotic magazine. Futaba decides to look at it in the toilet before class, but he suddenly faints after looking at it. When he wakes up, he looks in the mirror and sees… a blonde girl.

It turns out that when members of the Futaba clan become adults, they acquire the "ability" to change sex when aroused. This is how Futaba starts a new life in high school!