Mao is a young Japanese girl traveling with her cousin Mikio. Despite her sharp temper, she still respects and loves her cousin. And she has very unrelated feelings for him. On the train, Mao begins to be molested by a certain man who brazenly makes advances toward the girl. Seeing that her brother is a blatant lout and doesn't see many things, Kanzo starts chasing the couple all the way to the hotel.