For three months, the older sister and her brother-in-law, who lost his job, have been living with their younger brother. The younger brother pays his older sister a small fee for doing housework for her. One night, the younger brother feels something strange in his crotch as he watches his older sister comforting her depressed brother-in-law. One morning, the older sister lifts the duvet to clean the room and feels something strange when she sees her brother's erect penis. One day, while they are drinking together, the younger brother goes to a brothel...