Kaho Nikaidou, a sheltered fifteen-year-old, departs from her home and hopes for a fresh start in Tokyo. However, she never imagined nearly being hit by a truck! Fortunately, a good-looking stranger saves her just in time, and Kaho quickly develops feelings for him. With great courage, she confesses her love, and the handsome stranger agrees to go on a date with her. Unfortunately, Kaho's happiness is fleeting when she discovers that her new boyfriend happens to be a fifth grader!