Bad Guy is a 2010 South Korean melodrama television series, starring Kim Nam-gil, Han Ga-in, Kim Jae-wook, Oh Yeon-soo and Jung So-min. Directed by Lee Hyung-min, it aired on SBS from May 26 to August 5, 2010 on Wednesdays and Thursdays at 21:55 for 17 episodes.

Eun Guk and Eun Soo are siblings living alone after their father passed away. Eun Guk works at the post office. He feels like he is getting older, because of his younger sister's behavior like skipping school to attend an audition. Meanwhile, Eun Soo thinks her life is weary even though she is only 10-years-old. She thinks that because of her older brother, she can't pursue her dreams. Eun Soo then decides to leave for Seoul to achieve her dreams. One day, their mother appears in front of them.