Kanako Miyamae enrolls into the the all-girls school, Ame no Kisaki. On the way to the Girls Dorm she meets a girl named Shidō Mariya with her maid, Shinōji Matsurika. However, Kanako later discovers that Mariya turns out to be a boy. With Kanako's knowledge of the fact that Mariya is a boy, the former roommate of Kanako (Ryuuken Ishima) is replaced by none other than Mariya himself.

The Virgin Mary Festival is going to be held. After Kanako was voted to be a member in the planning committee, she asks the student council president for advice because she doesn't know much about the festival.

It's finally summer and so the swimming sessions begins. Kanako is very excited because at the swimming lessons she can see all the girls in their swimsuits. But during the fact that she daydreams and father Kanae interrupting (even once being out for the whole day because of food poisoning by way of eating raw liver), she collapses very often and because of that has to stay in bed. But she can go to the pool after all before the summer break begins and there she tries to reveal the fact that Mariya is a boy. However, it is revealed that Mariya got his twin sister, Shizu, to take his place.