Heaven Phantomhive, an English aristocrat of the 19th century, aged 12, is the heir of a successful business of toys and treats. He lives in a mansion with only the company of his servants, including his faithful butler named Sebastian. He is in fact a demon with whom the child has made a pact. Thus, the boy offered him his soul in exchange for his protection and until he realizes a mysterious revenge. Meanwhile, Heaven and his butler solve various criminal cases with the aim of eradicating the crime of their country.