A female college student is masturbating by imagining many things while watching a movie: imagining sex between a sister-in-law and her brother-in-law, imagining sex between a daughter-in-law and her father-in-law, etc. While she was masturbating, she moaned loudly and was caught by her stepbrother. The woman's body gets hot and cannot hold it, so she seduces her stepbrother.
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.
Two women, Hae-na and Hee-na, prey on men under the pretense of marriage. One of these men is a doctor who falls for Hae-na and showers her with luxury gifts, but that's all he does. She can hardly get in touch physically with him. Meanwhile, Hae-na meets Ji-hoon, her former lover, again by chance, but after finding out about his relationship with Hee-na, the three decide to pursue money rather than love and start working for the men around them.
Chae-yeon, who has never been in a relationship, secretly has a crush on Nam-gyoo, the president of her company, and practices kissing in front of the mirror every day. One day, Chae-yeon musters up her courage and asks Nam-gyoo to kiss her, but Nam-gyoo avoids her, promising her next time. But in fact, Nam-gyoo has never kissed properly before, so he goes to take kissing lessons to fulfill Chae-yeon's request.
Jeong-cha is a sexless married man. Although he is married, he secretly likes his manager, who is the only hot spot in the company. One day, Jeong-cha discovers a strange relationship with her boss, and the manager learns that there is a secret contract between the two of them. Jeong-cha sticks around by her side to sign a contract with her manager.
Ji-hoon, who is a loving husband, is always worried due to his premature ejaculation. He can only last for 10 seconds after insertion, so he just keeps caressing his wife for a long time, as he always feels afraid that he will finish quickly. At her wife's urging, he began consulting with a psychiatrist. When Tae-woo, another patient with a similar problem whom he met at the hospital, discovers his illness, the two become true friends who share each other's pain.
Yoon-yool and Min-seong go out to a company dinner with their bosses, Yeon-joo and Han-yeong. Min-seong had to carry Yoon-yool, who is passed out due to alcohol, on the way to her home. When Yoon-yool wakes up to take a shower, she is surprised to see Min-seong inside her room. Min-seong became excited when he saw Yoon-yool wearing only a towel and couldn't hold on to the temptation to lust for her body.
Seong-ae, who was innocent as a child, had her first relationship with Geon-woo, who was a jobless gangster in the neighborhood. Seong-ae, who was curious, opened her eyes to sex after having a relationship with her brother. As an adult, Seong-ae looks ordinary and plain on the outside, but perhaps because of her experience with her first man, her sex has become rougher since then. During her school days, she was tricked by her best friend, Yoo-ri, into stealing Geon-woo, and eventually, the two are now married. However, Geon-woo still meets Seong-ae from time to time secretly without Yoo-ri's knowledge and enjoys sex. Meanwhile, Yoo-ri also enjoys secret sex without her husband's knowledge with Myeong-jin, a junior at Geon-woo's company. Later on, Yoo-ri becomes tired of Myeong-jin, introduces him to Seong-ae as patronage, and tells them to enjoy sex. Seong-ae, who knows but is deceived, begins to expose the relationship between Gun-woo and Yoo-ri to the world.
Jang-hyeok, a man Yoo-jin has a crush on, meets her at his mother's request, but he hates Yoo-jin. Yoo-jin knows that Jang-hyeok doesn't like her, so she asks her best friend, Si-nae, to meet Jang-hyeok. Si-nae and Jang-hyeok fall for each other and get married. However, Si-nae, who likes alcohol and men, enjoys an extramarital affair with Sang-min. On the other hand, Yoo-jin becomes unrecognizably pretty, and Jang-hyeok falls in love with her.
Manager Jeong falls in love at first sight with the president's wife who came to deliver the goods to the company. Bo-yeong takes her on a phonetic basis to make her her own woman, and after that, Bo-yeong begins to cross the river that she can't escape.