A bratty high school student, the school sweetheart who has nothing to do all day long, after a strange time travel, he actually entered the body of the world's number one killer. How does a kid who has never stepped on an ant spend his career in the martial arts world? It's really troublesome~ Fortunately, this killer has a beautiful appearance, which allows him to work part-time as a thief who specializes in stealing the hearts of the beauties in the world.