Mirei has been married for four years. She has been undergoing fertility treatment, but has not been blessed with a child, so she continues to have obligatory sex with her husband. One day, her younger brother comes to stay at the house and suddenly tries to rape Mirei. The brother-in-law's intense desire awakens the parched woman in Mirei, and she accepts it. The brother-in-law takes advantage of the daytime when his brother is not around and begins training Mirei. Her father-in-law witnesses this and forces her to give him a blowjob. After her father-in-law and brother-in-law train her to have sex, Mirei becomes pregnant...