Aniki no Niizuma ~Otto no Koto ga Suki na no ni....~

Natsumi lives a happy life with her husband. However, she is worried about his younger brother, Kurou, who lives together with them, because of his delinquency. But one day, when she is involved in a trouble, Kurou saves her and she says, "I'll do anything for you." Like this, she sleeps with Kurou... At first, she doesn't want it, but she gradually gets addicted to his techniques... Days later, Haruka, her younger sister suddenly visits their house and sees them having sex...