Lee Heeseung (21) has never worked a day in his life and has lived like a king since his father, a famous rock star, died and left him his fortune. But everything changes when he realizes his manager has stolen his money. He gets a job babysitting Jungwon (7), a boy whose serious attitude is the opposite of his own. With the help of his girlfriend, he tries to bond with Jungwon in order to learn how to mature.