While looking for the cause of Mai's Adolescence Syndrome, Sakuta ends up scheduling a date with Mai. On the day they promised, Sakuta tries to help out a lost little girl on his way towards Fujisawa Station. But, he is misunderstood to be a perverted maniac by another girl, and because of that, he ends up arriving late to his appointed time to meet Mai. He somehow gains Mai's forgiveness and they proceed with their date, but Mai changes their destination, and takes Sakuta to Shichirigahama Beach...
Puberty Syndrome—a rumored, mysterious syndrome that only affects those in their puberty. For example, a bunny girl suddenly appeared in front of Sakuta Azusagawa. The bunny girl's real identity is Mai Sakurajima, a teenage celebrity who is currently an inactive high school senior. For some reason, her charming figure does not reflect in the eyes of others. In the course of revealing the mystery behind this phenomenon, Sakuta begins to explore his feelings towards Mai. Set in a city where the skies and seas shine, Sakuta unfolds the meaning behind his bizarre encounters on women with the said syndrome.
