Twins Shion and Mion have Keiichi seeing double. But as he grows closer to Shion, their flirty friendship has Mion seeing red. When Shion and Keiichi trespass on sacred ground the night of the Cotton Drifting, a string of gruesome murders and disappearances follow. Are the legends of Oyashiro-sama's curse true? Is there a demon in Hinamizawa?