One day, a friend of "Kurumi's" husband came to her house for a visit. They got home and had a good time talking about sex. Kurumi, who had been leading an ordinary life, was intrigued by what they were talking about. She gets some money and has relations with her friend while her husband is away. She gets a taste of it, and she gets deeper and deeper into the relationship with her friend. The man feels guilty, but he can't put in on it. And then... Kurumi's husband gets in the way, and she decides to put him to away for good.