Hyeon-joo and Chan-sik became a sexless couple as she had suspicions that her husband was cheating on her. Then one day, she heads to her in-laws' house to take care of her father-in-law, Man-geun, who lives alone for the time being due to an accident. Without a wife, Chan-sik enjoys an affair with her employee but is caught by his father.

How do inmates in a correctional facility satisfy their sexual desires? A full-fledged confined-space erotic story depicting the precarious prison life of prison guards and inmates involved in sex penpals begins!

Jeong-ho fights with Ye-rin. He happened to meet Eun-jeong, the wife of a senior who passed away. He tried to win Eun-jeong's heart, who was once his first love, but she has no intentions to date another man because of her husband. Instead, Ji-hye who lives with Eun-jeong falls in love with Jeong-ho. Ji-hye is trying to match loner Eun-jeong with the junior of his husband, Joon-hyeok, but is uncomfortable. Will Jeong-ho be able to love Eun-jeong?