Tall and shapely Yamashita Karen was active as an event companion before marriage. During work, she met her husband, who runs a home electronics company, and their relationship began. Sharing a mutual passion for motorcycles, they enjoyed riding together as a couple. However, on the tenth year of their marriage, she discovered her husband's infidelity. Deeply betrayed and heartbroken, Yamashita became emotionally distant, and their relationship quickly deteriorated. Seeking escape, she turned to an affair website, hoping to relieve her stress through sex with new men, but none satisfied her. Unwilling to let things end that way, she resolved to meet and test herself against a professional in sex.