Yoo Yakwoo, who turned 18 this year, is an ordinary eunuch, except that he loves cleaning. He was given the nickname 'Cleaning Ghost'. One day, the eunuch who was cleaning the Emperor's private office and the palace is overworked. As a result, Yakwoo receives a recommendation to fill the spot. "No, I can't…", "What do you mean you can't? Didn't you say with your mouth that dirty things should be cleaned?", "B-But… Emperor…", "Suck it. Take a deeper bite. Close your lips and suck it properly." However, Yakwoo cleans not only the Emperor's building but also the Emperor's 'objects'.