When Masaki Shiina, a student living in the dorms of an all-boys college, wakes up one morning, he discovers that he now has the body of a woman! Since Masaki is surrounded by young guys, if this news gets out, he's in danger of being taken to bed before he can do the deed as a guy...!! Unfortunately, Masaki's roommate, Yuuki Kashii, quickly discovers his secret. In return for his silence, Yuuki demands that they have some fun together. Even though Masaki resists this at first, he starts to get addicted to the bodily pleasures!!