A year has passed since Natsumi's family moved to the city from the mountain village of Hinamizawa. Natsumi has become acquainted with her new life, surrounded by friends, living peacefully from day to day. But a special breaking news report one day will change everything. A toxic gas disaster has occurred at a rural village. And the village that got caught in the disaster is Hinamizawa, where Natsumi's family used to live. Shocked by the incident, Natsumi's grandmother tells her "this is Oyashiro-sama's curse." What is this "Oyashiro-sama's curse" that grandmother is speaking of...?