A married man who has abstained from sex for 773 days engages in a passionate extramarital affair with an unprotected woman, Tsukino Kasumi (HZGD-293).

"Kasumi" proactively contacted her husband's boss, Oshima, whom she had been observing for a while, and seduced him into having an affair... She thought it would just be a minor indiscretion, but she didn't expect Oshima's penis to be different from her husband's; no matter how many times he ejaculated, it wouldn't go soft. Kasumi became addicted to this unparalleled thrusting. Although she knew it was wrong, she still indulged in sex, not going home until dawn, indulging in sexual pleasure, reaching orgasms to the point of near death—an affair indeed!