Kyouhei, Ranmaru, Takenaga, and Yukinojou are beautiful, handsome, young men living in a huge mansion. One day, their landlord, whom they call "Auntie", asks them a favor: to make her niece, Sunako, who's going to be living with them,
into a respectable young lady. She agrees to make their living expenses free of charge if they succeed, but if they fail, she'll triple their rent. Due to their confidence in knowing how to deal with women, they agree, but once they meet Sunako, they begin to realize that their lovely living arrangements may soon be in jeopardy.