Dr. Cameron (George Zucco) has succeeded in his expierments with a serum which will turn a man into a wolf-like monster and is ready to avenge himself on the men who caused his professional failure. He uses it on his gardener Petro (Glenn Strange) and one after the other is killed by his creation. His daughter, Lenora (Anne Nagel), grows suspicious and confides with newspaper reporter Tom Gregory (Johnny Downs).
Summary written by Les Adams {longhorn@abilene.com}

Directed by Sam Newfield
 
Writing credits (in alphabetical order) Fred Myton
 
Cast (in credits order)
Johnny Downs...Tom Gregory
George Zucco....Dr. Lorenzo Cameron
Anne Nagel....Lenora Cameron
Glenn Strange....Petro
Sarah Padden....Grandmother
Gordon De Main....Prof. Fitzgerald
Mae Busch....Susan
Reginald Barlow....Prof. Warwick
Robert Strange....Prof. Blaine
Henry Hall....Country Doctor
Ed Cassidy....Father
Eddie Holden....Jed Harper
John Elliott...Prof. Hatfield
Slim Whitaker....Officer Dugan
Gil Patric....Detective Lieutenant