In Fujisawa, where the skies are bright and the seas glisten, Azusagawa Sakuta is in his second year of high school. His blissful days with his girlfriend and upperclassman, Sakurajima Mai, are interrupted with the appearance of his first crush, Makinohara Shouko. For reasons unknown, he encounters two Shoukos: one in middle school and another who has become an adult.

As Sakuta finds himself helplessly living with Shouko, the adult Shouko leads him around by the nose, causing a huge rift in his relationship with Mai. In the midst of all of this, he discovers that the middle school Shouko is suffering from a grave illness and his scar begins to throb...

[Source: Aniplex]