Plot Summary

In London, the American college student Alex Campbell and his British girlfriend Patricia Wilson stumble upon a fainted man in the tube stairway in Russell Square. Patricia forces Alex to look for a guard to help the man but when they arrive, the man is gone. When the sarcastic Inspector Calhoun learns that the missing man is an Officer of the Order of the British Empire, he asks Detective Sergeant Rogers to bring the couple to the precinct to confirm that the man was alive. Meanwhile MI5 agent Stratton-Villiers assumes the case and orders Calhoun to leave. However, there are other cases of missing persons in that station and Calhoun proceeds the investigation. What the officers do not know is that there is a cannibal survivor from a collapse in the tunnel in 1892 living in the underground that is kidnapping passengers to feed and to have companionship.