Ji-hyeon and Min-soo are a younger couple who just got married and started a family. For Ji-hyeon, Min-soo is a perfect husband without shortcomings, but the only downside is that she is not satisfied with her younger husband's sexual life due to her strong sexual desire. Then one day, Ji-hyeon, who accidentally placed an order through a delivery app, found out about a delivery man named Dong-hoon who came to their home to drink a glass of water, and then she finally crossed the line. Ji-hyeon, who has tasted the thrill that she has never felt from Min-soo, visits Dong-hoon every night, and her husband Min-soo spends each day with her without knowing this... The love game between a man and a woman, who cannot be seen at all, is just beginning.

Two men love one woman. Seo-yeon chooses who to have a relationship with, every time. Jin-woo and Dong-hyeon competes with Seo-yeon's attention, but she doesn't think the setup is strange. Actually, there is a reason why she doesn't want to choose between the two. Who will win Seo-yeon's love in the end? The unending love story between the three is just beginning.

Ji-min, Hyeon-soo, and Woo-yeong, play together at Ji-min's house. Hyeon-soo happened to see Ji-min change her clothes while playing. Hyeon-soo, who secretly likes Ji-min, ran away excitedly after seeing Ji-min's skin. Woo-yeong, who saw Hyeon-soo like that, actually made a funny suggestion to Ji-min who was his sex partner. Ji-min calls Hyepn-soo and uses the fact that Hyeon-soo likes him to have sex. Hyeon-soo moves according to Woo-yepng's plan.

Yoo-jeong and So-hyeon are not real siblings but have lived together since childhood. So-hyeon is caught by Yoo-jeong spending time at home with her boyfriend. Min-soo saw Yoo-jeong naked in the bathroom. Yoo-jeong is interested in such Min-soo and seduces Min-soo. Min-soo knows that Yoo-jeong and So-hyun are not real sisters and approaches Yoo-jeong right away. So-hyeon finds out and So-hyeon breaks up with Min-soo. Min-soo played with two sisters...

Jun-ho and Min-soo, experience a hard time because of Da-hee who drinks whenever she breaks up with her boyfriend, but they still take care of her. But they heard that Da-hee is meeting her ex-boyfriend again. Actually, the two guys like Da-hee. They’re trying to make sure that Da-hee won't meet her boyfriend again. The love story between the two men, which is invisible to the eye, is just about to happen.

Three people clean up the house for Min-soo who is new to the house. Yeong-cheol, who has become close friends while living in one house, is obsessed with Seo-yeon because he does not like Min-soo. Seo-yeon knows the relationship between the two and has a strange confidence watching the fight between the two. The fierce fight between the two men trying to win the relationship with Seo-yeon before Min-soo enters the house! The story of the unknown end is just beginning.

Three childhood friends finally gathered. From the first meeting, it's not so bad. Na-yeong enters the house, angry at Min-hyeok and Jin-woo who broke their promise. After living apart for several years, they lived in one house. Three people who are childhood friends but not ordinary friends. When one person disappears, the secret between the two is revealed... Who can develop from a friend to a lover... The unknown story begins now.

Having been happily married to Jae-hyun, Na-yeon accidentally learns about Jae-hyeon's wishes from her former sex partner Min-woo. Na-yeon, who is a little nervous after hearing Min-woo's words, confirms with Jae-hyeon and spends another night with Min-woo in anger. Min-woo, who had long been interested in Na-yeon, now begins to approach her as a real man, not as a sex partner, and she begins to open her heart little by little. The love story of two men surrounding a woman is just beginning.

Elementary school friends Min-soo, Woo-hyeon and Ji-yeong are close friends who still hang out with each other even if they're now older. Min-soo likes Ji-yeong but he knows that his best friend, Woo-hyeon, likes Ji-yeong too. He is hesitating to confess. One day, Min-soo who happened to spend the night with Ji-yeong was happy that he told Woo-hyeon that he was going to sleep with Ji-yeong as if nothing happened, and Ji-yeong also thought nothing about it. The story of three young people agonizing between strong friendship and love is just beginning.