On a rainy day, a woman's dead body is found in an apartment. Female detective Kazuko is in charge of the case. Although Kazuko has a happy life with her family, she can't disconnect her relationship with her lover. While trying to unravel the mysterious murder case, Kazuko finds out the secret of university assistant professor Mitsuko and Izumi who is a devoted housewife. Her husband is a popular novelist.
- Native title: 恋の罪
- Also Known as: Koi no Tsumi