Kouta Ochiai is a thirteen-year-old middle schooler with a workaholic father who announces a move to Sapporo, leaving the boy to fend for himself while the paperwork is sorted. On the way home he meets Natsuki Hagiwara, a seventeen-year-old who decides, on a whim, to move in and look after him. Four years older and full of eccentric habits, Natsuki upends Kouta's quiet routine, turning meals, homework and his crush on a classmate into daily skirmishes with a girl he barely knows.