Six months ago, Sakuta Azusagawa stumbled upon a bunny girl at the library and has been joyfully dating her ever since. However, his past crush, Shouko Makinohara, resurfaces as an adult and creates chaos in his relationship with Mai Sakurajima. Additionally, a middle school-aged Shouko is hospitalized and her proximity causes Sakuta's old scars to ache unexpectedly. As Shouko's predicament concentrates on Sakuta, he must confront his emotions head-on. With a girl's fate on the line, how will he proceed?