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.

After encountering various girls going through Puberty Syndrome, Sakuta Azusagawa's high school days have come to a close, and he is now a university student. He enrolls at a university in Kanazawa-hakkei alongside his girlfriend Mai Sakurajima, a nationally famed actress. Off campus, he stumbles upon an out-of-season miniskirt Santa. Precognitive dreams, an anonymous online singer, poltergeists buzzing on social media... A mysterious tale with enigmatic phenomenons surrounding girls with wavering hearts starts again. Puberty continues...