One day, Miu Takigawa suddenly receives a letter notifying her that she has been chosen as a member of a brand-new project. Half in disbelief, she heads over to the location stated on the letter. There, she finds seven other girls summoned there in the same fashion. The girls behold a giant, top-secret facility. They stand in bewilderment as they are told: "You are going to debut for a major record label as an idol group." A new kind of idol, never-before-seen, is about to be born here...

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.