Open Marriage

Koharu thought she was living a happy married life with her husband, although she no longer had the passion of her romantic days. One day, however, her husband Shuuichi suddenly introduces her to his “girlfriend” and, to top it all off, proposes an “open marriage”: they maintain their marital relationship but have extramarital affairs with others. Koharu is shocked and at first resists extramarital romance, but after signing a lover's contract with Hayamiya, a senior whom she had a crush on in junior high school, she gradually……!?