Fate: The Servant of the Night.

Ha Yeon-woo, a popular low-class guy, has only one girl, So Yeon, the love of his dreams, in his heart. After touching Oh-dong's nerves by mistake, he is put in danger, but Hwigeon and Cheon Ilhong save him to use him for their revenge on Byeok Family. Yeon-woo forcibly becomes a servant in Byeok Family to save his sister taken hostage, and there he reunites with Oh-dong and So Yeon.