Kim Ki-woo (Choi Woo-sik) and his family live on the edge of poverty. They fold pizza boxes for a delivery company to make some cash, steal wi-fi from the coffee shop nearby, and leave the windows open when the neighborhood is being fumigated to deal with their own infestation. Kim Ki-woo’s life changes when a friend offers to recommend him as an English tutor for a girl he’s been working with as the friend has to go out of the country for a while. The friend is in love with the young girl and doesn’t want another tutor “slavering” over her. Why he trusts Kim Ki-woo given what we know and learn about him is a valid question. The young man changes his name to Kevin and begins tutoring Park Da-hye (Jung Ziso), who immediately falls for him, of course. Kevin has a much deeper plan. He’s going to get his whole family into this house. He quickly convinces the mother Yeon-kyo, the excellent Jo Yeo-jeong, that the son of the house needs an art tutor, which allows Kevin’s sister “Jessica” (Park So-dam) to enter the picture. Before long, mom and dad are in the Park house too, and it seems like everything is going perfectly for the Kim family. The Parks seem to be happy too. And then everything changes.