Junya, who lost her mother a few years ago, lived with her father on a three-legged race. My father brought Mayu, his remarriage partner, at the end of summer when Junya was about to take the exam. For Junya, living with Mayu, who is too young to be called a mother, was a series of embarrassment and temptation. It is inevitable that a young boy who has just reached puberty suddenly appears and is aware of his young mother-in-law as a woman.