Kurenai no Tsuki  The hand of an Oni with a ring is found on the bed of a river. The police finds out that the hand belongs to a woman, missing for a month, and closes the case, but the husband can't believe that his wife was a monster and so he instructs the young detective Kouya Karasuma to investigate. While exploring the forest, the boy gets lost; it's already evening when he hears some voices and decides to ask for directions. He therefore ends on the edge of a pond where two girls are having a bath, but he faints due to fatigue. When he wakes up, he finds himself in a house: the two girls' mother tells him that, having seen them naked, he has to marry one of them, as required by the rules of Saginomiya family. Kouya asks for time to think, discovering that in the village there's a legend about the existence of an Oni and there are rumors that Saginomiya family is in some ways involved.