Junya, who lost his mother a few years ago, lived with his father in his three -legged race. His father brought Mayu, his partner remarried, at the end of the summer when Junya was about to take the exam. For Junya, life with Mayu, who is too young to call her mother, is a series of confusing and temptations. The fact that a boy who has just entered adolescence suddenly appears and realizes that the young mother -in -law is a woman is unavoidable.