Kana thought she had a happy, comfortable marriage until she discovered her husband's affair. One day she goes out to distract herself and accidentally leaves her wedding ring at home. A younger adult man approaches, seeing only a lonely single woman. Thrilled that someone still finds her desirable, she impulsively claims she is unmarried and accepts his advances. Their casual encounter grows into an ongoing sexual relationship, he falls genuinely in love, and Kana becomes trapped in a lie from which there is no return.