Soo Min moved to a urology department in the provinces, so she came to Dae Hyeon's house to lodge. Soo Min, who happened to be interested in seeing Dae Hyeon's genitals, suggests a part-time job to study Dae Hyeon's genitals, but Dae Hyeon, a test taker, is not interested in Soo Min. Hee Jin and Dae Hyeon live in Cheol Soo's boarding house. Hee Jin earns her living expenses through political affairs with Cheol Soo. Upon learning of this fact, Soo Min informs Dae Hyeon that Hee Jin and Cheol Soo had an affair. Knowing that the allowance from Hee Jin was Hee Jin's sexual labor, Dae Hyeon decided not to accept Hee Jin's money anymore and accepted Su Min's offer of part-time job.

Young Sister and the Secret Deal

Woo-seok happens to meet Gyeong-seo on the street and heads to Gyeong-seo's house. Woo-seok against Gyeong-seo while talking to Gyeong-seo in Gyeong-seo's house. But Gyeong-seo is busy, so she doesn't want to meet a man. Rather, Nam-joo, who lives with Gyeong-seo, falls in love with Woo-seok, and the two of them fall in love in a daze. When Nam-joo fell in love, she felt sorry for the longitude of being alone. Nam-joo decides to connect Gyeong-seo and Jeong-woo by making plans with Woo-seok. In the end, Gyeong-seo and Jeong-woo share love with each other through their performances. But Woo-seok can't erase the scripture from his mind.

Husband Friend

Jeong-hyeok happens to meet In-joo, a former karaoke helper, in his neighborhood while being bored with his married life with Eun-hye. In-joo sees Jeong-hyeok's affair and takes advantage of it and asks him for money, but Jeong-hyeok seduces her to swapping because he will give her more money. In-joo, who needed travel funds with her lover Woo-seong, allows swapping and begins to swap. Embarrassed by his lover's and husband's swapping proposal, Woo-seong and Eun-hye are forced to share the swapping. Then Woo-seong and Eun-hye are attracted to each other, and they meet secretly.

Swapping, That Dangerous Sex

College girl and the guy next door! Cousin and the woman next door! Min-joo likes her cousin Min-cheol, but Min-cheol rejects her. Min-joo, whose self-esteem has fallen, seduces Yeong-seok, the guy next door, to regain his self-esteem. Yeong-seok's wife, Soo-jin, is having an affair with Min-cheol.  The four secret private lives are exposed by chance, and Yeong-seok and Soo-jin use Min-joo and Min-cheol's minds to continue their affair.