A strange plague strikes a Cornish village, and local doctor Peter Tompson enlists the aid of Sir James Forbes, his former professor, who comes to the town with his daughter, Sylvia. When the two doctors open the graves of the victims to perform autopsies, they find the coffins empty. The walking corpses are seen near an abandoned mine on the estate of Clive Hamilton, the local squire who learned voodoo in Haiti and created the zombies to work the mine. Peter's wife is killed; and Sylvia, under Hamilton's evil spell, goes to the mine where she is captured by Hamilton and his zombies. Peter and Sir James arrive in time to save Sylvia from being sacrificed and to start a fire in which Hamilton and all his zombies are destroyed.