Shizuoka, March 2019. The town where Shiira, a first-year high school student, lives is said that will sink to the bottom of the sea if a major earthquake strikes, but he is fine with that as he still has the past of his mother's death in his mind. Shiira's childhood friend, Anko, has feelings for him and asks him to go to Tokyo with her. One day, however, Shiira meets a woman on a cruise ship, and the wheels of fate begin to move.