Sung-joo and Joo-hee moved into a new house next to Jong-gyu and Min-joo. Joo-hee gives out ddeok to tell them they've moved in next door. Jong-gyu falls in love with Joo-hee at once and thinks about having sex with her. Meanwhile, Sung-joo goes next door to borrow a tool and he falls for Min-joo. The husbands are attracted to each others' wives and soon they cross the line.