Ordinary teenage boy, Ootaki Kazumi, opens his front door one day to discover a case of luggage. To his surprise, the contents of the box included a girl and styrofoam popcorn. Sabrina is a girl claiming to be the illegitimate child of a Italian mafia boss. Protected and sheltered from the outside world by her parents, but due to circumstances she'll be living with Kazumi for a while.

A romantic comedy about a naive girl whose new-found brother has to deal with the complications of a teenage boy and girl living under the same room. Complications arise.