|Steve Railsback||Colonel Tom Carlsen|
|Peter Firth||Colonel Colin Caine/Security Officer on phone|
|Mathilda May||Space Girl|
|Patrick Stewart||Dr. Armstrong|
|Michael Gothard||Dr. Bukovsky|
|Frank Finlay||Dr. Hans Fallada|
When a space mission involving American and British astronauts encounters an alien craft, the humanoids within are brought aboard the shuttle. Back on Earth, one of the extraterrestrials, who appears to be a gorgeous woman, proceeds to suck the life force out of various Londoners, turning the town into a city of roaming half-dead people. When Tom Carlsen, a surviving astronaut, realizes what is happening, he sets out to stop the ruthless alien presence.