Relative Sister.

Chan-joon, living with an open-minded relative sister. I don't care about Chan-joon at all, such as bringing my boyfriend home and having sex. That's why Chan-joon began to meet another man after receiving a sex break-up after having sex with his girlfriend. Heartbroken Chan-joon saves Bo Ra from being forced into dating by her boyfriend. Bo ra is curiously drawn while looking at Chan-joon, who was hurt in a quarrel. After the conflict, Bo ra enters Chan-joon's room.