Gook Young Soo is a high school Korean language teacher. He is on bad terms with Joo Bok Man, a high school student in his 40s and the landlord. Joo's two sons and Guk's three daughters also live in Joo's house, and everyone becomes involved in various incidents and relationships, including romance. The show depicts the lives of a group of characters in the sitcom having nicknames ending with ko.