Joon-soo learns that his friend Hee-gyu's sister Hee-jin has no where to go after being scammed, so he suggests living with him. The two start living together. They are close like brother and sister but they can never be that. The two start getting funny and Joon-soo can't go to sleep at the thought of Hee-jin sleeping just a wall away from him. Mi-na, Joon-soo's girlfriend notices Joon-soo changing and seduces Joon-soo at his house where Hee-jin is. Is it the girlfriend or the sister?
Park Cho-hyeon
as Jo Hui-jin
Min Joon
as Oh Jun-soo
So Yoon
as Choi Mi-na
Joo In-cheol
as Han Jae-suk
Seo Joon-yeol
as Jo Hui-kyu
Lee Kyeong-joon
as Head of department (부장)
Hong Doo-ri
as Stockings girl (스타킹 녀)
Ah Ri
as Jun-soo's Mother (Cameo)
