Kang Chil Woo is a lowly officer during the Joseon era. Chil Woo is not a very smart and one of his life long goals is to become a midlevel officer. However when night falls, he is no longer that low level officer but instead a top assassin in an assassination organization. He gives out punishment to criminals and gives justice where needed. So Yoon and Chil Woo have a tragic love story. Yeon Doo is the daughter of a fallen yangban who owns a textile shop. She falls in love with Chil Woo after he rescues her from thugs who were harassing her.