Heisuke just came into town and the first thing on his to do list is chasing pretty girls, which causes him to get punched in the process. After reaching the house he'll be staying at he sees a girl trying to sneek inside. Seeing this as a perfect opportunity to legitimately grope a girl, he attempts to stop this intruder only to find out that it's the same girl who punched him earlier, not only that but her name is Umi and she just happens to be one of the three sisters who live in that house along with their mother. The next day Umi finds out that Heisuke is a boxer who's skill is only eclipsed by his letcherousness.