The events take place in Victorian England. A child who suddenly loses all his loved ones finds himself on the brink of death. At that moment a demon appears to him and offers to strike a deal: his soul in exchange for the chance to take revenge. Several years later, Siel Phantomhayv—nicknamed "the Queen"s Chain Dog"—is the head of a thriving corporation called Phantomhayv. He handles all company affairs and secretly works for the Queen of England. His main partner and support is butler Sebastian Michaelis, who is also a demon to whom Siel sold his soul. The story recounts the adventures of Siel with his butler and their servants, as they search for the cause of Siel"s family"s death and his thirst for vengeance against those responsible.
A-1 Pictures Inc. Japan