A young man grows up with his older cousin who is like an older sister to him. When he grows up, he goes to visit her at her home where her friend is also visiting. The three of them under roof make for some interesting circumstances.

Eun-hye is a substitute lecturer. One day she is freaked out by being stalked and calls her cousin in to live with her as her bodyguard. Kang-tae is a test repeater and he's impressed with how hard working Eun-hye is and starts feeling fond of her. One day, he drinks with his friend Tae-bum and gets drunk while talking about his cousin.

Yeon-jae, who runs a wedding dress shop, decides to use her cousin, Dong-sik, who just got out of prison as her part-time worker, and lets him stay in her house. A sexy employee named Ji-na feels attracted to Dong-sik and flirts with him. Yeon-jae gets back together with Yeon-woo, the photographer, but is shocked to find out that he’s in a deep relationship with Ji-na. Yeon-jae gets drunk alone and crosses the line with her cousin Dong-sik…

Freshman college students turned friends, Jang-hee and So-hyeon, will be having their first blind date. Jang-hee and So-hyeon met Won-ho andDoo-sim through a blind date over drinks. Doo-sim, a sophomore asks Jang-hee and So-hyeon to call him 'oppa', however Won-ho teases him that he is younger than them. Jang-hee who is older than Doo-sim, jokes him to call her 'nuna', and then...