2010. A drunken student, Koo Jae-hee, catches her classmate Jang Heung-soo in a racy situation outside a club. The next day, in order to stop the dirty gossip, the girl pretends in front of the whole group that they are dating. Jae-hee and Heung-su develop a great friendship: they spend more and more time with each other and soon start living together.