The Four Skulls of Jonathan Drake opens with a Shakespearean quote ("The evil that men do lives after them") as we see professor of the occult Jonathan Drake (Eduard Franz) sitting in his study. He is in the grip of a powerful, terrifying hallucination of three floating human skulls and seems on the verge of a heart attack. His daughter Alison (Valerie French) finds him there and is very concerned for his health. Drake brushes her fears aside and seems to be regaining his reason until Alison mentions a message from her Uncle Kenneth. It seems the older man wrote to tell about having recently seen a tsantsas, or shrunken head. This news startles Jonathan and he immediately makes plans to go to his older brother's home even though the trip will take at least two days. But the night Kenneth receives Jonathan's wire announcing his imminent arrival, Kenneth is attacked in his bedroom by a fearsome, dark-skinned man whose lips are sewn together.
This grim man paralyzes his victim by sticking him in the neck with a poisoned wooden needle but before he can remove the stricken Kenneth's head, a servant interrupts him.
Showing a great deal of common sense, Alison calls ahead of her father and asks the local police to check up on her uncle Ken. Lt. Jeff Rowan (Grant Richards) shows up at his house only to learn that Mr. Drake has died the previous night! Drake's personal physician Dr. Bradford (Howard Wendall) is on hand, as well as archeologist Dr. Emil Zurich (The Body Snatcher's Henry Daniell). Bradford explains that his patient has died of natural causes and reveals that heart trouble runs in the family. It seems that almost all the Drake men die of heart failure at around the age of 60. Lt. Rowan questions everyone, learning that Dr. Zurich had called to visit Kenneth Drake at his request to give some information about a shrunken head found outside the house. Zurich is an expert on the Indian tribes of South America. Rowan is perplexed by the death, but as there's no evidence of any crime he lets it drop.
We are then shown Dr. Zurich's home life, which consists of lounging about his basement in a robe, boiling strange fluids over a fire pit and shrinking heads! And not just any heads, either. Zurich has a deep hatred of the Drake family and his only servant is the tightlipped fellow with the knife and needle, Zutai (Paul Wexler). Frustrated that his assassin failed to bring home the prize, he sends him out again. As soon as Drake's body is placed in state the Indian darts in and nabs that noggin. Jonathan arrives just in time for the funeral, and when his brother's head is discovered to be missing, he nearly collapses. That night he unburdens himself to Alison, telling her the family secret. It seems that the girl's great-great grandfather retaliated against a tribe of Jivaro Indians in the Amazon jungle after they killed one of his agents. He wiped out the entire village save the witchdoctor, who escaped and placed a curse on the family that all male descendants would die at 60 and lose their heads. Since then the two male Drakes that have reached that advanced age have mysteriously died and their heads disappeared — only to have the fleshless skulls turn up in the sealed family crypt. No one knows how this is done but since Kenneth's head has disappeared his brother is waiting for a third skull to materialize in the vault. Alison runs to Lt. Rowan and clues him in to this odd story, which neither of them believe. However, when they visit the vault together they spot Zutai in the area and the cop takes a shot at him. Checking the crypt afterwards, they find that there are now three skulls in place. Hmmm.
Although we are privy to the whodunit aspect early on the film still has the cops carefully follow clues, keeping a veneer of believability that makes things fun. When Rowan has the police lab man dust the three skulls in the crypt turning up small skulls etched into the fingerprints its a eerie site that is handled well. Its easy to point out the film's silly flaws, such as the stagebound look of the outdoor sets, the crypt with electric lighting, that Jonathan Drake only seems to be about two days younger than his brother, or that Zutai's knife suddenly goes all rubbery in the climatic struggle. But the film overcomes these small details to be one of the rough gems of the period's scare pictures. It's far from a classic and its never going to win over a negative crowd but to a receptive audience it is 70 minutes of pure cheesy fun.