Mei Misaki, a resident of Yomiyama City, has just started a new semester and her twin sister Misaki Fujioka visits her to spend the last days of summer. During her visit, they explore various local spots, including shopping centers and shooting stalls. However, Mei is uneasy about her new class, which is rumored to be cursed. This unease is compounded when Mei sees what she believes is an omen of death in her sister.