Airi was to be left at a relative's house while her parents were out. However, living in that house were three middle-aged brothers, Ichiro, Jiro, and Saburo, who couldn't get married in a good year. The three people, who have lived a life that has no connection with the opposite sex and children, collapse their reason to the innocent loveliness of Airi who does not look like this house, and instead commits Airi who can not resist with fear.
