A wonderfully atmospheric outing from Hammer Films, who diverged from their often successful variations on Universal's classic monsters into the world of zombies, a genre which had yet to receive its infusion of terrifying new blood with the 1968 classic Night of the Living Dead. The plot, which owes a debt to the Bela Lugosi chiller White Zombie, involves a mad Cornish squire, who solves an annoying labor crisis in his tin mines by turning local villagers into voodoo-controlled zombies. Dr. Thompson (Brook Williams) and his daughter Alice (Jacqueline Pearce) soon discover the unpleasant nocturnal habits of the shambling undead slaves -- including their tendency to go on murderous rampages when not directly under the squire's control. At the request of Alice, Sir James Forbes (André Morell) arrives on the scene to investigate. The superb script by Peter Bryan employs an interesting subtext about the rift between the British aristocracy and the exploited working class, but the film is less a political allegory than a spooky, atmospheric horror opus that ranks among Hammer Films' finest.