Twenty years ago, a poisonous gas erupted from a nearby swamp and killed thousands of people in the village of Hinamizawa. In the years since the "Great Hinamizawa Disaster," people have avoided the town and prefer to forget that it ever existed. However, on one particular night, five strangers find their way to this abandoned village tucked away in the mountains.

In Yoigoshi-hen—a possible future outcome of Tsumihoroboshi-hen—Mion Sonozaki, a former resident of the village, arrives at Hinamizawa's now-dilapidated Furude Shrine, seeking shelter from the rain. Along the way, she meets Akira Otobe, whose friends have disappeared. As they enter the shrine, they find others already there, also taking shelter. But when a murder takes place among them, suspicions run high, and some begin to suspect Mion herself: after all, Mion died in the Great Hinamizawa Disaster 20 years ago.