A Western-style mansion stands in a remote area, far from civilization. 　Hiruta, a scientist who studies moths, lives there with his two daughters, Junko and Yuko, and in the basement of the mansion, their insane mother is held captive. 　Junko, who is blind in one eye due to an injury she suffered as a child, is jealous of the beautiful Yuko and is always harsh to her. 　However, Junko is not Hiruta's real daughter. 　Thirteen years ago, when Junko and Yuko were still babies, Hiruta, who had lost his wife, worked as an assistant to Dr. Fujita Kazuo, an authority in the medical field. 　Hiruta's child, Yuko, was cared for by Dr. Fujita's wife along with Junko, who was born around the same time. 　One day, Dr. Fujita succeeded in extracting a compound from moth scales that dramatically increased healing abilities.