Description
Late one night at the Russell Square station in the London Underground, university students Patricia and her American exchange student boyfriend Alex find an unconscious man on the stairwell. Fearing that he may be diabetic, Patricia checks his wallet and finds a card that reads James Manfred, OBE. They inform a police officer, but find that Manfred has vanished. Inspector Calhoun is assigned to look into the disappearance. Calhoun questions Alex and suggests that he and Patricia robbed the man.
Calhoun's colleague tells him about the history of the London Underground, particularly the Victorian railway workers who constructed the tunnels under dire conditions, and an urban legend that a group of descendants who survived an 1892 cave-in still live belowground. Meanwhile, one of the last surviving members of a family of these railway workers watches his female companion die; they have survived in the underground by resorting to cannibalism of the patrons. In an empty chamber, Manfred's body lies, mutilated. The man, now left in complete solitude, goes into a rage and brutally murders three maintenance workers.
One night, Alex and Patricia take a train home and get off at Holborn station. Patricia realizes she forgot her textbooks on the train. Alex attempts to retrieve them, but the doors close before he can exit; Patricia yells that she will meet him at home. Once the train leaves however, Patricia is attacked by the cannibal man and incapacitated. When she fails to meet him at their flat, Alex seeks help from Calhoun, who is dismissive. Alex returns to Holborn station and enters the tunnel. He breaches an abandoned area of the Underground and finds remnants of the miners who worked there over a century ago. Meanwhile, Patricia awakens in the cannibal's lair. She finds him to be aphasic and unable to communicate with her. She hits him over the head and manages to escape into a tunnel. He corners her and attempts to communicate with her, but becomes frustrated and violently attacks.
Alex finds them and begins fighting with the cannibal. Patricia begs Alex not to hurt him, and they watch as the cannibal stumbles into a passageway. Calhoun and several other detectives discover Alex and Patricia. As they search through the abandoned section, they uncover a room full of corpses laid in bunk beds – the generations of survivors from the cave-in that occurred a century before. There they find the cannibal, bleeding profusely, and he collapses in front of them, apparently dead. The detectives return meet Alex and Patricia, and head to the station platform. After they leave, the cannibal screams "Mind the doors!" as the credits roll.