An ordinary Korean Kim family lives a hard life. They have to live in a dank, dirty basement, stealing wi-fi Internet from their neighbors, and work odd jobs. One day, a friend of the son of the family, leaving for an internship abroad, offers to replace him and work as a tutor for a high school student in a rich family Park. Having forged a higher education document, the guy goes to a chic designer mansion and makes a good impression on the hostess. Immediately, he comes up with an unusual plan to employ his sister.