Puberty syndrome - This is a mysterious phenomenon that only occurs during the sensitive and unstable puberty. For example, a wild bunny girl appeared in front of Sakuta Azusagawa. Her real identity is Mai Sakurajima, a senior high school student and an actress who is on hiatus from her star activities. Her charming figure is invisible to the people around her for some reason. Sakuta decided to solve this mystery. During the time spent with Mai, Sakuta learned her secret thoughts... Heroines appeared around Sakuta one after another, and they all had "puberty syndrome". In a small town where the sky and the sea are shining, an exciting story begins.