This Gothic latecomer brings to mind the cobwebbed horrors that preceded it without sadly ever getting into a groove of its own.

Sir Joel Cadman (Rathbone) has discovered a drug from East Asia that he has dubbed “the black sleep.” It places its user in a death-like state, severing any feeling in the user’s nerves until the time that they awaken from its hold. Cadman first uses the narcotic to allow his colleague Dr. Ramsay (Rudley) to escape the hangman’s knot after the latter is accused of the murder of a money-lender (Johnson).

After restoring Ramsay to consciousness, Cadman enlists the young physician in his mission to utilize “the black sleep” for the advancement of surgical science. Turns out Cadman’s wife has been in a coma ever since the development of a brain tumor and the doctor is desperate to find a means of successfully removing it. He has operated on others before, including his mute manservant Mongo (Chaney, Jr.), though the after effects have been a little less than satisfactory.

Ramsay begins to suspect that Cadman’s motivations are making him blind to what he’s doing to his patients, especially when he discovers that Mongo is the father of Laurie Monroe (Blair), a nurse in Cadman’s employ.

With Cadman demanding a higher supply of patients from dubious acquaintance Odo (Tamiroff), it becomes clear that the old doctor will stop at nothing to further the advancement of science… even if it means turning every last patient into a gibbering freak!

The Black Sleep hits all the necessary beats for this type of macabre melodrama, but it doesn’t bring anything new to the table or invest a sense of fun in its material, so it ends up as a curious leftover from the decade of aliens and atomic monsters.

The few pumps of energy that it does squeeze out of it—including at least one juicy brain shot and our heroes’ descent into Cadman’s cave of mutated patients—eventually fizzle out before we’re back to the same routine. Most of the cast itself seems to be slumbering through the movie.

Even old pros like Rathbone don’t hit the mark, his villainous Cadman never quite coming off as the unhinged fellow that he is rather than just seeming slightly rude and British.

It’s also quite painful to see Chaney and Lugosi in this picture, both wasted by their addictions, required to do nothing more than literally shuffle around (Chaney is at least allowed a short fight scene with fellow bit heavy Tor Johnson).

Carradine only shows up at the very end of the film as one of Cadman’s freaks, here essaying a kind of “Sayer of the Law” role and endlessly ordering his cohorts to “Kill, kill, kill!” The one enjoyable turn in the film comes from Tamiroff’s Odo, as the actor milks his body-snatching gypsy for every slimy drop that he can.

Even as things gear up for the big finale—with even a nurse catching on fire (!)—it all ends with a whimper as Cadman escapes the vengeful clutches of his victims by accidentally falling down a short stairwell.

That incident is paradigmatic of The Black Sleep itself: just when it has a good thing going, it manages to disappoint on the execution.