A year after losing her husband in an accident, Sayuri (Yuno Hoshi) has been living with her brother-in-law and his wife, who run a hospital, along with her son. Enduring the harsh and cruel treatment from her spiteful brother-in-law and sister-in-law (Miho Wakabayashi), Sayuri finds emotional support only in her son, Shinji. However, the couple's sexually degrading abuse escalates relentlessly, eventually targeting Shinji as well. Amid this torment, a certain unique skill possessed by Sayuri becomes the turning point that changes their fate.