Kosumo has a serious medical condition that landed her in a hospital ever since she was a child. Since Kosumo's blood type is the rare AB negative, it is next to impossible to find a donor. While she was on the verge of death, out in the city, the 99th Generation Miko, Himiko-sama got into a terrible accident while trying to save the life of a child. She was rushed to the hospital and that’s when Himiko and Kosumo's fates crossed. Since it was obvious that Himiko was surely going to die as a result of the accident, the hospital decided to use her as a donor for Kosumo’s condition after they discovered that she also has the rare AB negative blood type. Kosumo got better and moved back to Tokyo, and later found out that Himiko’s heart and blood aren’t the only thing flowing inside her…