Miki (Hinako Sakurai) is a high school student. One day, her parents tell her that they are going to divorce and swap partners with the Matsuuras, a couple they met on a trip to Hawaii. Miki's parents also tell her that the Matsuura couple have a son named Yuu (Ryo Yoshizawa). They will all live together in the same house. After that, the two families begin to live together and Miki becomes attracted to Yuu. He does not talk much, but is kind.