Three young half brothers, Ichitaro, Takeshi and Tsuguo, are moving from a traditional Japanese house near a river to the suburbs. With little experience living together as a happy family, their relationship gradually transforms over the course of a week when their cousin Sakeko arrives to help them prepare to move. Although they had played together as children, the brothers are embarrassed by her presence at first. As the brothers and their cousin negotiate the delicate balance of emotions between them, the film ponders the differences between secret love, a passing emotion and new love.