Overcome by grief after the accidental death of his wife, respected university professor Dr. Julian Blair (Boris Karloff) becomes obsessed with using his experiments to communicate with her. Having captured her brain waves on a machine, Blair must find a receptor for them, and tries using a single live subject. After several failures, Blair quits his university job and hides out in a small New England town, where he adds more unsuspecting subjects -- both alive and dead -- to his experiments.