夫が単身赴任で身体のほてりを持て余していた人妻「ありさ」の家に妹の彼氏がやってきた。何もなく終わるはずだったが、無防備すぎるありさの肢体と爆乳に我慢できなくなった彼氏に言い寄られてしまう。ダメだと分かりつつも男日照りの身体は性欲を抑えきれず…。妹の彼氏と濃厚に求め合った誰にも言えない不倫関係。

The boyfriend of the young*r sister came to the house of the married woman "Arisa" who was having a hot body because the husband went to work alone. It was supposed to end without any trouble, but the boyfriend, who couldn't resist Arisa's body and big breasts that are too defenseless, makes a pass at her. Even though she knows she shouldn't, Arisa's body can't contain her sexual desire... She and her sister's boyfriend have an affair that cannot be told to anyone.