In a Cornish village during World War II, a German Nazi uses the disguise of a headless ghost to strike fear into the local tin mine workers.
Posing as a man the British Army has rejected for active duty, a mining engineer, Dr. Frederick Holmes (Lester Matthews), takes a week-long walking trip through Cornwall. The first time that we see Dr. Holmes, he is tramping about the foggy moors after dark and catches a ride with a peddler (Harold De Becker) to Morgan's Head. He wants to know why local miners refuse to work a tin mine that could yield a valuable asset to the English war effort. Holmes learns that the villagers are not working the mine because they fear the ghost of a headless man who haunts the moors and the mine.
Eventually, the engineer exposes the ghost as a hoax. As it turns out, the village benefactor, Sir Harry Leland (John Loder), has been masquerading as the headless ghost. Sir Harry explains that he is the offspring of German nobility who settled in England in the days of King George to supervise other Germans in the tin mines of Cornwall. He has turned the superstitious fears of the villagers against them to keep the mine out of operation. Sir Harry shoots a simple-minded villager who rushes him. He attacks Holmes, they struggle, and Sir Harry falls onto his knife and dies.
