Behind the Mask

Hard boiled Jack Holt escapes from prison. His gangster contacts set him up with a job as chauffeur at the large estate of one of their associates who is getting a little nervous. Holt's job is to keep an eye on said associate - whose attractive daughter Constance Cummings already knows there is something fishy going on.

It doesn't take long before we discover that Holt is not a real crook but an undercover agent hoping to track down the smugglers' big boss, the mysterious Mr. X.

Boris Karloff is fun as the loyal but not too bright henchman who does Mr. X's dirty jobs. Edward Van Sloan is a bit creepy as a suspicious-looking doctor running a very shady hospital. There's also a nurse named Bertha Mann at the house who spies on the family and phones in reports which she leaves on a very cool answering machine in an unknown location.

Constance Cummings has a good role as the daughter who is not content to sit back and let Holt chase the bad guys. Cummings and Holt are an effective pair of heroes in this fast-paced crime drama that offers few surprises but does feature some suspenseful moments, including an exciting climactic scene in the hospital.