A famous tower in Gangnam houses various businesses. The story begins with Kang Ji-young, a receptionist at a dermatology clinic in the building. Ji-young, who has been having an affair with a married doctor, realizes that he has another mistress. She suspects that the other woman might be her coworker, who has been bothering her for some time. As various human figures gather in this Gangnam building, ugly relationships and hidden stories begin to unfold...