My Wife's Friend who was Caught Messing Around

Joo Seung-gi and Yoo Ah-rin desperately have sex several times a day to have children, but they were not pregnant, so they were tested, and the result of the test was Seung-gi's infertility. After much consideration, Seung-gi asks his fiery friend Yoon-woo to have a relationship with Ah-rin, and after persistent persuasion, Ah-rin and Yoon-woo have a relationship. Afterwards, Seung-gi began to doubt the relationship between Yoon-woo and Ah-rin...

Jae-ho, who inherited his late father's elite company, hires Hyeon-jeong to help his younger brother Sang-ho, who has been retaking the college entrance exam for nine times, on his studies. However, during the study sessions, Sang-ho is only filled with thoughts of having sex with his private tutor. Meanwhile, Jae-ho, who has secretly loved Hyeon-jeong for a long time, confesses his feelings to her, and the two officially become lovers. But one day, Hyeon-jeong is betrayed by her friend Na-hee, whom she brought in to help tutor Sang-ho in English.

Yeong-tak and Ha-na are stepsiblings who live with the support of their divorced adoptive parents. The two begin taking individual private lessons for their respective careers. Yeong-tak secretly gives his acting teacher Na-ri sleeping pills to covet her body, while Ha-na is busy seducing her physical education teacher Han-cheol. Meanwhile, Na-ri and Han-cheol run into each other at the stepsiblings' house, fall in love at first sight, and seek revenge on the two who offended them.

Kim Hak-cheol is a trashy husband who sends his wife Jin Joo-hee to his friend Kang Min-hyeok as a housekeeper due to gambling debts. He visits his wife once in a while and steals money. He borrows money from Min-hyeok, a golden spooner who is Hak-cheol's friend, on the condition that Joo-hee is sent as a housekeeper. Min-hyeok is kind to his friend's wife, Joo-hee. Over time, the true colors begin to emerge. Meanwhile, Min-hyeok's wife, Nam Gyoo-ri, lives together with them without knowing anything about Joo-hee.

Yoo Mi-ri, a female president of a camping site where various guests gather, has CCTV installed everywhere in the campground and always records with an action cam to check on complaints she receives from guests. Doing things in this way has led her to develop the habit of observing people in advance. One day, an incident occurs where someone steals Mi-ri's underwear, which prompts her to observe guests more closely to catch this culprit. But unexpectedly, she finds out someone's secret, and that is someone's desire to burn himself with sex when lightning strikes.