Hiroko attends the memorial service of her fiancé, Itsuki Fujii, who died in a mountain-climbing incident. Although Itsuki's mother says that their old house is gone, Hiroko records the address listed under his name in his yearbook and sends him a letter. Surprisingly, she receives a reply, and discovers it came from his old classmate, a girl who also happens to be called Itsuki Fujii.
Believing that the world will end that very day, three mental patients Coco, Tsumuji, and Satoru set out upon a journey. Walking upon the tops of the walls of the city, they seek to find a picnic spot with the best vantage point to view the final event.
Shortly after moving to the suburbs, the Kobayashis start to come undone. Convinced a family curse is at the root of their erratic behavior, the man of the house takes it upon himself to course-correct before it takes the last of their sanity.
