Fact1: university students and American exchange student boyfriend find unconscious man in stairwell on verge of death, Fact2: Calhoun is assigned to look into disappearance, Fact3: group of descendants live below ground in abandoned section of tunnels, Fact4: Patricia is attacked by cannibal man Once platform, Fact5: Alex manages to breach abandoned area of Underground
Output: 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 in the stairwell on the verge of death. Fearing the man may be diabetic, Patricia checks his wallet and finds identification that reads James Manfred, OBE. Upon alerting two of the Scotland Yard, they return to the stairwell to find he has disappeared. Inspector Calhoun is assigned to look into the disappearance. Calhoun antagonistically questions Alex, who asserts the man was a drunkard, and suggests he and Patricia robbed the man. While discussing the case of the missing Manfred, Calhouns 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 cavein still live below ground in an abandoned section of the tunnels. 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 railway patrons. In an empty chamber, Manfreds body lies, mutilated. The man laments the womans death, as he is now left in complete solitude. The man goes into a rage and brutally murders several Underground employees in, taking one to his lair. Calhoun remains suspicious of Alex and Patricia, and calls Alex in for repeated interrogations. After seeing a film one night, Alex and Patricia take a train home and get off at Holborn station. While deboarding, Patricia realizes she forgot her textbooks on the train. Alex attempts to retrieve them, but the doors close before he can exit; just as the train leaves, Patricia yells through the window that she will meet him at home. Once the train exits the platform, Patricia is attacked by the cannibal man and incapacitated. When Patricia fails to meet him at their flat, Alex seeks help from Calhoun, who is dismissive of him. Alex returns to Holborn station to search for Patricia, and enters the tunnel against the orders of a station attendant. He manages to breach an abandoned area of the Underground that had caved in, and finds remnants of the miners who worked there over a century ago. Meanwhile, Patricia awakens in the cannibals lair. She finds him to be aphasic and unable to communicate with her. When he begins grabbing her aggressively, she hits him over the head and manages to flee, escaping into a tunnel. He finally corners her and attempts to communicate with her, but becomes frustrated and violently attacks her. Alex stumbles upon the scene and begins fighting with the cannibal, stomping him on the head. Patricia, however, begs Alex not to hurt him, and they watch as the cannibal stumbles into a passageway. Calhoun and several other detectives who have entered the Underground discover Alex and Patricia. As they search through the abandoned section of the Underground, the detectives uncover a room full of corpses laid in bunk beds – the generations of survivors from the cavein 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, who have been waiting outside the cannibals lair, and head to the station platform. After they leave, the cannibals indecipherable screaming echoes through the brick tunnel.