Arisawa Atsushi transfers to Jougaouka High School to be close to Shibata Masami (Ma-chan), his childhood crush. What Atsushi doesn't know is that Masami no longer works at the school, and his brother Shibata Masayoshi has taken over as the nurse. When Atsushi mistakes Masayoshi for Masami, he's shocked to find that "Ma-chan" seems to have undergone a complete personality reversal. To make matters worse, his friend Inagaki Kouji is deeply in love with him and constantly tries to kiss him, making Atsushi's life at Jougaoka a living nightmare. That is, until he begins to think that maybe the new Ma-chan isn't so bad after all, and perhaps he even likes the way Ma-chan is now. That is, of course, until he discovers that Masayoshi is not Masami.