Young Mother 4

Nineteen-year-old, Jin-goo enjoys an erotic moment to himself while thinking about his pretty English tutor. Then one day, he is caught in the middle of an embarrassing moment and becomes awkward with her. However, this becomes an opportunity and she starts teaching him sex. Their replationship becomes an uncontrollable romance. However, she quits the tutoring and the relationship to get married. Time goes on and Jin-goo is a grown up. He's used to thoughtless sex. However, his partner of benefit gets pregnant so he meets his future-mother-in-law to talk about marriage. However, she's so beautiful and sexy. He moves in with the in-laws but soon breaks out of the marrige due to his wife's fling. The mother-in-law doesn't know how to make it up to him for what her daughter has done. Jin-goo suggests something dangerous...

Yeong-gil is in graduate class and is stressed about getting a job. To make things worse, he's not had any experience with women yet, so he's always searching for something in his dreams but wakes up to nothing. Then one day, there is a change in his life, he puts his hand in The Box of Pandora and gets a job although it wasn't a regular position. He sleeps with his female superior during the interview even though it's not how he imagined it. Then one day, he visits Joo-yeon's home and meets her beautiful mother. Can he keep himself from being seduced by this woman?

Twenty year-old Ki-chan lives alone with his father. One day Yoon-seo (Kim Jeong-ah), his stepmother comes to live with them. She tries to be friendly with Ki-chan but he appraoches her as a woman and starts showing her that. Yoon-seo strongly rejects him but he knows that she wants him too. Their relationship turns into something dangerous. Then one day, Min-jeong, who has had a crush on Ki-chan for a long time, finds out what is going on between the two. The young stepmother fools her husband and falls in love with his son and the son falls in love with his father's woman. They make a deal with Min-jeong to make sure she doesn't say anything.

Woo-jin, who is a repeater of college entrance exam, and Taek-sik's friend, Kang-hee come and visit Woo-jin's hometown on a small island. Woo-jin's mom, Hyeon-sook operates a small sashimi restaurant and a bed and breakfast to make a living on the island. Although Hyeon-sook has sex with Bong-seong, she rejects his proposals. One day, Woo-jin is terribly shocked to accidentally see his mom Hyeon-sook and Bong-seong having sex.