Just before the new semester begins, Misaki Fujioka travels to Yomiyama City to see her twin sister, Mei Misaki. The sisters take full advantage of the remaining summer days, wandering through a town exhausted by the heat and stopping at various spots, such as a shopping mall and a shooting gallery. While exploring Mei's basement, Mei voices her discomfort regarding her new class, which is rumored to be cursed. Seeking further amusement, the twins choose to go to the local amusement park. However, the relaxation of a drowsy summer afternoon may quickly turn tragic when Mei perceives the color of death on her sister—a clear sign that a disaster is destined to occur.