Seiya has never had sex. One day, his anxious father puts him into girls' high school. On his first day at school, he meets Kotone, his old friend, but he feels ill. She gives him a medicine and he takes it. However, the medicine is not for cold. It was invented by her and once he/she takes it, his/her every body part will be reinforced. "Ok, I'll dominate this school!" A battle for Seiya between teachers and students now starts!!!