After intrepid working girl Mary Carter becomes the new owner of a reputedly haunted mansion located off the Cuban coast, a stranger phones warning her to stay away from the castle. Undaunted, Mary sets sail for Cuba with a stowaway in her trunk—wise-cracking Larry Lawrence, a radio announcer who helps Mary get to the bottom of the voodoo magic, zombies and ghosts that supposedly curse the spooky estate.
Ten years after the death of millionaire Cyrus Norman, his will is to be read out to his six relatives, including Joyce Norman and Wally Campbell. Organized by Norman's lawyer, Crosby, the six meet at Norman's eerie New Orleans Gothic mansion. During the reading, the superstitious housekeeper declares that someone will be dead by midnight. Wally fears for Joyce when she is declared the sole inheritor, but all are alarmed when Crosby turns up dead.
Four explorers are summoned to Peru by the brilliant physicist Dr Thorkel. They discover a rich source of radium and a half-mad Thorkel who shrinks them down to one-fifth their normal size when they threaten to stop his unorthodox experimentation.
