High jump champion Izumi Sano has realized that his slender new roommate Miyuki is a girl, but he's decided to keep her secret so she doesn't get kicked out of their all-boys' high school. Now they're becoming good friends, without worrying about "guy" or "girl" stuff - or so Miyuki thought until Izumi kissed her one night! Before Miyuki has time to freak out, in steps a bigger problem: her American half-brother Shizuki, who's not too thrilled to find out that his little sister is cross-dressing 24 hours a day. But handsome Shizuki has problems of his own...