Who would this middle-aged woman, who received 30,000 yen, have sex with? (Mariko Koto, JUR-664)

Mariko works as a clerk. Her unassuming demeanor ignores even the younger employees. At home, her husband is indifferent. She fills her daily loneliness with masturbation. Mariko has a stronger sex drive than others. One day, at an izakaya (Japanese pub) with her juniors, she overhears a young man say, "Give 30,000 yen and you can have sex with a mature woman." Although she's considered a suspicious older woman, Mariko exchanges contact information with him. Then they actually meet. Desperately suppressing her nervousness and excitement, she clutches the brown paper envelope containing 30,000 yen…