Six months ago, Sakuta Azusagawa had a chance encounter with a bunny girl in a library. Ever since then, he's been blissfully happy with his girlfriend: Mai Sakurajima, that same bunny girl. However, the reappearance of his mysterious first crush, the now-adult Shouko Makinohara, adds a new complication to his relationship with Mai. To make matters worse, he then encounters a middle school Shouko in the hospital, suffering from a grave illness. Mysteriously, his old scars begin throbbing whenever he's near her. With Shouko's bizarre situation somehow revolving around him, Sakuta will need to come to terms with his own conflicting feelings, for better or worse. With a girl's life in his hands, just what can he do? In Fujisawa, where the skies are bright and the seas glisten, Sakuta Azusagawa is in his second year of high school. His blissful days with his girlfriend and upperclassman, Mai Sakurajima, are interrupted with the appearance of his first crush, Shouko Makinohara. For reasons unknown, he encounters two Shouko's: one in middle school and another who has become an adult.