The film's storyline concerns a discredited mad scientist who plots to kill his colleagues one-by-one using a secret formula that transforms his simple-minded gardener into a murderous wolfman.

Cameron injects a serum made from a wolf's blood into the cooperative Petro, who loses consciousness, grows fur and fangs, and awakens after he has transformed into a wolfman.

Cameron turns to an empty table, visualizing his former colleagues sitting there; the four professors dismissed his theory that wolf blood transfusions could be used to give a human being wolf-like traits.

He recalls how the scientific community, the press, and the public joined in a resounding chorus of ridicule that finally cost him his position at the university.

Cameron's daughter Lenora is romantically involved with Tom Gregory, a newspaper reporter investigating the death of the little girl.

[3] Although sources such as Phil Hardy's The Encyclopedia of Horror Movies stated the film was shot in five days, the Hollywood Reporter production charts and Daily Variety indicate that shooting required two weeks.

"[3] "Eddy" of Variety declared the film had a "childish, almost naïve attempt to inject horror" and that the dialogue and situations were "strung over.

"[6] Eddy found Anne Nagel and George Zucco as "satisfactory" while Strange was "properly horrible as the beast-man.