Boring, long, and too preachy.

Tells a fascinating and unsettling true story, and does so well, without pretending to have all the answers.

If you like to be scared, if you like to laugh, and if you like to learn a thing or two at the movies, this absolutely cannot be missed.

It’s not bad or unwatchable but despite the amplitude of the spectacle, the end result is underwhelming.

Jack Holt, at this time, was Columbia's top star, helping, along with Frank Capra, to catapult the studio into the "almost" big time with films like "Submarine", "Flight" and "Dirigible". He was also their workhorse and a funny running gag in the biography "King Cohn" had various male stars going to Harry Cohn for a raise, of which he would agree provided they "don't tell Jack Holt". Holt started work on his latest action film "In the Secret Service" in November 1931 but when "Frankenstein" proved such a big hit, the story was changed to incorporate some gruesome scenes to justify it's publicity as a horror film and given the more ambiguous title of "Behind the Mask".This has a definite feel of a cliffhanger serial condensed into an tight hour and is a terrific little movie. At the film's start Jack Holt, as Jack Hart is in prison and has made a confidante of Henderson (Boris Karloff). Hart is planning a breakout that night and Henderson, who is due to be released in the lawful way, is suitably impressed and thinks his organisation could use him. But Hart is a secret service man who is on the trail of the elusive Dr. X, whose identity is hidden even from his own gang members. He is given a job as a chauffeur to Arnold (Claude King), a gang member who is having second thoughts about his own involvement - not so his daughter, Julie (Constance Cummings) who makes a friend of Hart and tries to help him in every way. Ruling the house is the dreaded Edwards (Bertha Mann in her last film), the right hand woman of Dr. X, who, when people get too hard to handle, books them into Eastlake Hospital for an "operation". This opens up the film for some pretty grizzly scenes - dithering Arnold has already been taken to the hospital but is dead by the time Jack and Julie arrive. Julie is then rushed to hospital for an emergency appendectomy where she amazingly overpowers her captors and rushes to save Hart when he is just about to undergo an operation without the use of anesthetic!!! "It is only when I begin to cut on the inside that you will realise an experience. To me it will be ecstasy"!! - fiendish is not too strong a word for Dr. Steiner (Edward Van Sloane), whose evil characterization was up there with Dr. Fu Manchu and the crazed doctor in "The Mystery of the Wax Museum".A lot of action is packed into the hour, which again gives it a Saturday morning serial feel - an operative (Thomas Jackson, from "Little Caesar") walks off to his death, Hart's duplicity is discovered and Henderson arranges an "accident" at sea and Arnold's body is dug up, only to find his coffin is filled with drugs. Beautiful Constance Cummings was an asset to any movie, she had real intelligence and was not just a pretty face. She gives a lot more to her role than was originally there and really fleshes out her part.Highly Recommended.

Although the film has Boris Karloff in it, he is not the star. Jack Holt stars in the movie though today few would recognize this star of the 1920s and 1930s. He died relatively young and his son, Tim, is more well known today.The film begins with Holt and Karloff in prison and they are talking about getting out--Holt is planning on breaking out and Karloff says he has some friends who will get him out, but is a bit evasive about what this means. A bit later, you see Holt pretending to escape--he apparently is some sort of government agent. Here is the crazy part--to make it look more realistic, he actually shoots himself in the arm in a scene that is a bit hard to watch. A short time later, Holt is able to insinuate himself into a criminal gang, as they buy his story about the escape. It seems that Holt's job is to infiltrate the gang headed by the mysterious 'Mr. X'! For the most part, this is a mindless sort of adventure film--the sort that makes no sense but has one crazy cliff-hanger sort of scene after another. It makes for a brainless but interesting sort of movie--the sort that kids at the time would have liked and parents would have tolerated (or at least tried). When seen today, however, I can't see anyone particularly enjoying this tripe--especially since Karloff lovers like myself just won't get enough of the actor's performance to make it worth our time. Cheap and silly--with little to recommend it.

A macabre mystery with many elements of the supernatural/shudder scientific genres.Boris Karloff plays a lead henchman in the service of a mysterious Mr. X. His performance does not suggest a red herring role, but he is sinister enough as a grim-faced gangster to keep one's interest throughout the picture. Early on, it seems possible that the sinister Dr. Steiner played by Edward van Sloan may seem to be a more likely candidate for Mr. X., but his performance raises enough doubts to keep the viewer in a constant state of suspense.A very fine "B" feature for the night owl crowd.7/10.Dan Basinger

This film was made during the same period as "The Criminal Code" by the same studio. It also used some of the same sets and film footage. During this period,"Frankenstein" was released and Columbia decided to play up Karloff's name and the picture's horror aspects in the advertising. But technically, it is not a horror film. It is exploited as another horror picture, this doesn't horrify sufficiently to class with preceding baby-scarers. The scare stuff seems tossed in regardless of where it fits, but it gets results because KARLOFF's threatening pan makes him a natural for his part.