Kyohei tells Hibino about what happened in Karakami village... A young female teacher, Senou Chihaya, became close to a lonely Aki.  But his stepbrother Atsushi wants to make her his own.  Chihaya is isolated from the rest of the village for disobeying their rules.  Soon after, Chihaya dies protecting Aki from Atsushi's Kuramitsuha.  Kuramitsuha was once Aki's, and when he gets it back, disaster strikes...
This place has its own rules.