Mizuki Ashiya has such a crush on a track star named Izumi Sano that she moves from the U.S. to Japan to enroll in the all-male high school he goes to! Pretending to be a boy, Mizuki becomes Sano's roommate...but how can she keep such a big secret when she's so close to the guy she wants?

Mizuki and Sano are now a couple in private, but she fears what will happen when he discovers that she's not a boy. Meanwhile, the dorm leaders have learned there is a girl living among them at Osaka High, and they are determined to find out who it is!