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 civilization succumbs to a deadly pandemic and his wife is murdered, a special forces soldier abandons his duty and becomes a hermit in the Nordic wilderness. Years later, a wounded woman appears on his doorstep. She's escaped from a lab and her pursuers believe her blood is the key to a worldwide cure. He's hesitant to get involved, but all doubts are cast aside when he discovers her pursuer is none other than Commander Stone, the man that murdered his wife some years ago.