The film tells the story of the night watchman night watchman working from 9 pm to 5 am each night to protect people Chosun secret behest of the king, they investigate the mysterious case Chosun and they have the ability to see ghosts. "The Night Watchman", is a romantic drama, fiction about three powers in the world: those who deny the existence of the devil, those who use them, and those who try to remove them.