After living with her sister, her husband (who is also her brother-in-law who lost his job), and her younger brother for three months. The younger brother was paying his sister a small amount as a part-time job for doing housework. One night, the younger brother feels something strange in his crotch while watching his sister comfort her depressed brother-in-law. One morning, when she tries to clean the room and takes off the duvet, the sister feels something strange when she sees her brother's erect dick. One day, while drinking together, it is discovered that the younger brother is paying a considerable amount of money to the hostess club. "Eh!? You're paying that much? It's a waste! Give me that amount as my fee w ahaha w" The younger brother was confused by his sister's words, but when he jokingly offered to negotiate, she said, "Hmm? If you give me a fee, that's fine w?" With the influence of alcohol and a strange vibe, they start checking each other's compatibility, and they both start to get excited and end up in a situation where they can't stop... The sister and brother, while resigning themselves to the situation, cross the line and escalate further and further...