This made news on release as Boris Karloff's first role back in UK after his success in Universal monster films. So a supernatural subplot was inserted into a crime story about assorted crooks in pursuit of a priceless diamond. Karloff plays a dying Egyptologist who seeks eternal life by being buried with the enchanted jewel.
So he is the ghoul who returns from his crypt to track down the robber who steals it. There are the usual archetypes of early horror films, with the gaunt solicitor who reads the will, a bickering but intrepid couple who fall in love, the ominous Egyptian collector, the idiotic comic relief and, in his screen debut, Ralph Richardson as the imposter.
Best of all is Ernest Thesiger as the sinister, faithful servant. Boris is only in the film for the opening 15 minutes and briefly at the climax, but he does give the film stature. This is a much more interesting story than The Mummy which Karloff starred in a year earlier. And the production holds up well too. It's splendidly photographed with excellent sets.
This is a kind of horror-pantomime; an old dark house story in which the actors give broad, melodramatic performances. It's quite spooky, and creaky, and not at all scary. It was presumed lost for many years. Often those films turn out to be not much when rediscovered, but this is great fun and a significant entry in the Karloff legend.