Ten years have passed since their mother's death, and Mizuno Hideo, her widower, has become the dominant figure controlling the lives of the two sisters. Once kind, Hideo's obsession has deepened over time, transforming him into a man who now tightly binds them. The elder sister, Natsuko, is 35; the younger sister, Kozue, is 30. Having given up on ordinary lives, the sisters find their only solace in each other, indulging daily in physical intimacy. Is their pleasure an addiction or a price paid? What fate awaits them at the end of this path?