Yeon-joo (Kim Hye-soo) is a single mother who lives in a two-story townhouse with her young daughter. To help pay the bills, she decides to rent out the second floor of the house. Her tenant is Chang-in (Han Seok-Kyu), who claims to be a writer. Although he seems like an ordinary guy, Chang-in seems to have come to the house with a purpose, and sneaks around when he can. That would seem like cause for eviction for most, but Yeon-joo isn’t like most landlords and is suffering with a bout of depression. Meanwhile, her daughter is going through a normal teenage obsession with her looks, so she doesn’t notice his odd behavior either. But even though neither one of them is actively trying to put a stop to Chang-in’s behavior, their respective problems serve to thwart his plans.