At midnight on Christmas Eve in the mid-19th century,[3] somewhere in Russia,[3] two fugitives fleeing persecution stop by the roadside for the woman to have her baby.

One night, Etoile changes into a wolfman under the influence of the full moon, and kills a circus member, Tiny.

That same day, a group of prostitutes from a nearby brothel visit to have lunch, and Etoile is smitten by the pretty Christine.

Christine confronts Etoile the next morning, and in the ensuing argument, she tells him about her history as an orphan until Madame Tellier took her in.

The attacks draw the interest of Professor Paul Cataflanque, a skilled forensic pathologist, who initially deduces that it was a wolf.

He embarks on his own investigation against the protests of his friend, Inspector Gerard, and inspects the wolves in Etoile's zoo.

The evidence leads him to the brothel, and he questions Madame Tellier, who is put out by his requests to identify the bodies.

Meanwhile, the Prefect of Police decides to make Paul's wolf theory official, and orders all zoos to kill their wolves.

With his rage and grief spurring his viciousness, Etoile goes on a killing spree, and hides in the sewers the next day.

Paul discovers one of the victims is still alive, and revives her long enough to hear her speak of a creature neither a man nor a wolf.