Night Key often gets slapped together with other horror movies in some of those cheap-o multi-movie boxes. That's how I found the film. It, along with other lesser-known Boris Karloff features like Tower of London, The Climax, The Strange Door, and The Black Castle, was priced at $5 at my local public library. They were having a big sale, so I cleaned up.
The problem is that Night Key, which was the last film to bill Boris Karloff as just "Karloff," is not a horror movie. Rather, it's a mash-up of science fiction and crime, with neither element dominating or even being all that convincing. The sci-fi comes in the form of David Mallory (played by Karloff), a brilliant inventor whose latest patent has just been rejected by Stephen Ranger (played by Samuel S. Hinds). Ranger, who runs a highly scientific security company with a small army of uniformed and badge-wearing security guards, has a history with Mallory. In the past, both men tried to woo the same girl, but with Mallory winning her hand. The two married and had a beautiful daughter (played by Jean Rogers). Ranger has never forgotten this, so when Mallory and his corrupt lawyer approach Ranger with Mallory's grand achievement--a burglar alarm that uses a shortwave frequency--Ranger buys the product but refuses to put it into action. Ranger decides that the new system, which is superior to the one that Ranger's company uses, is better off buried.
Although he's just made a payday, Mallory decides to pass on the deal. For him, it's either put the system into play immediately or there's no deal at all. Besides a long-simmering rivalry, Mallory is also inspired by his rapidly failing eyesight. When Ranger stands firm, Mallory decides to take his system's "key," which is a small radio box that can unlock any door protected by Ranger's alarm system, and cause a little mischief. Now known as The Night Key, Mallory starts breaking into stores protected by Ranger Security and rearranges everything. He doesn't steal, just musses up the place so that the Ranger boys know that they don't stand a chance against him until they adopt the new system.
Mallory has a partner in crime. Called Petty Louie (played by Hobart Cavanaugh), he's a repeat loser who spends most of the film in an stolen overcoat that is way too big for him. Although Petty Louie likes his new boss, he can't understand why Mallory won't cash-in on his new system. Night Key plays up this confusion for comedic value, as Mallory keeps finding Louie's sticky finger attempts everywhere. In the end, Petty Louie redeems himself and dies a hero after a couple of heavies try to kill off Mallory.
Of course, even though the audience is supposed to root for Mallory and Petty Louie, they are never allowed to forget that The Night Key is still a criminal. (And besides, at this point, Karloff wasn't allowed to play completely above-board characters, anyway.) In order to balance out Mallory's gray, the audience is given something white. Enter Officer Jimmy Travis (played by J. Warren Hull). Travis is one of Ranger's top men and a very active security guard. Travis is originally given the task of catching Mallory and bringing him back to Ranger headquarters, but as the investigation grinds on, Travis falls in love with Mallory's daughter Joan. The closer he gets to Joan, the more Travis suspects that Ranger is the real bad guy in situation. So, near the film's climax, Travis quits Ranger Security in order to save Mallory and earn Joan's hand.
The reason why Mallory needs saving changes halfway through the film. By that point, Ranger Security is less of a worry than The Kid (played by Alan Baxter), a monotone gangster who wants Mallory's invention in order to rob the city blind. After getting Mallory through Petty Louie, The Kid and his goons force Mallory to play along. But Mallory is resistant. He first smashes the machine, then when he is forced to repair it in captivity, he switches the frequency, thereby making the key an alarm in itself. During their planned heist, The Kid's men unwittingly give off their location to the Ranger boys. Travis jumps into action, helps to rescue Mallory from the ABC Moving Company, which is a front for The Kid's outfit, then pursues The Kid from a cop's running board. Ultimately, The Kid falls because Mallory, from the backseat of The Kid's car, uses the key in order to shorten The Kid's breaks during a high-speed chase. The Kid then gets captured by Travis and a combined NYPD-Ranger force, while Mallory catches Joan and Travis getting tongue happy in the back of The Kid's car. Fin.
Night Key came out during a weird time. By 1937, the Universal monster boom was over. The Hays Code had essentially tamed Hollywood, noir was at least a decade away, and most science fiction enthusiasts were confined to the pulps and did not make up a sizable amount of moviegoers. Night Key shows traces of this confusion, for at times it doesn't really know what kind of movie it is. Sometimes is hot for machines; at other times it wants to be a hardboiled mobster flick. Some horror even tries to creep in, but the only scary thing about Night Key is the power of Ranger's company, which seems more competent and more technologically advanced than the city's police force. Still, Night Key does have some up sides. Most of the performances are great (Karloff and Hinds play dueling egoists to near perfection), while the movie is itself beautiful to watch, what with its great black-and-white photography. While a B-movie at best, Night Key is fun and very imaginative. Not bad for a cheap DVD staple.