Young workers are dying because of a mysterious epidemic in a little village in Cornwall. Doctor Thompson is helpless and asks professor James Forbes for help. The professor and his daughter Sylvia travel to Thomson. Terrible things happen soon, beyond imagination or reality. Dead people are seen near an old, unused mine. Late people seem to live suddenly. Professor Forbes presumes that black magic is involved and someone has extraordinary power. He doesn't know how close he is: the dead become alive because of a magic voodoo-ritual, and so they must serve their master as mindless zombies...