Two couples vacation together. They were friends and campus couples in college. Meeting again after the years passed sparks new attractions.

When I was a high school student, my sister was a sexy friend who kept me from falling asleep with all kinds of delusions every night. Min-soo's thrilling delusion catches fire after she accidentally meets her naked sister at home. After becoming an adult, Minsu and his friend Yong Joon get a job at a sister company. From her sexy friend, Minsu's secret work towards her, who is now reunited as a sexy female warrior, begins...

Dae-sung and Jung-won have been married for two years. They are car pooling with the married couple next door. Woo-sung and Tae-hee don't interfere with each others' lives. However, these two couple don't just share cars, they share each others' wives too...

Joon-ho falls for his new step-mother, Min-joo. He suppresses his feelings because she is his father's woman, but one day his father passes away. In addition, the step-mother has been throwing him signs and her daughter Eun-jung leaves the house. Joon-ho is alone with Min-joo and he comforts her for losing her husband. However, he ends up comforting her not just mentally, but physically as well.