At age thirteen, Mizuki Ashiya, a Japanese girl growing up in America, saw Izumi Sano high jump on TV for the first time. Amazed by his grace, Mizuki quickly became a huge fan of Sano's. Three years later, high-school age Mizuki decides to return to Japan so that a dream of hers might come true: to see Sano jump in person. Mizuki even goes so far as to transfer into Sano's school, in hopes of being closer to him. Mizuki's wish is granted, and she becomes Sano's roommate. There are two problems, however: Sano has quit the high jump, and he attends an all-boys school, meaning Mizuki now has to disguise herself as a boy morning, noon and night, even in her own room! Unknown to Mizuki, however, Sano finds out her secret fairly quickly, and now a strange feeling has come over the two of them...
