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The story is both science fiction and black comedy, dealing satirically with the declining economy and the culture of greed and conspicuous consumption associated with the 1980s. It posits a world in which the "haves" — the monied elite, the yuppies — are in fact space aliens seeking to oppress the "have nots" — poverty-stricken Earthlings — through subliminal advertising in the mass media.
The film stars former wrestling professional Roddy Piper as a homeless laborer who falls in with a group of shantytown rebels who have invented special dark glasses that enable the wearer to see past the facade the aliens have constructed to prevent their detection. One of the film's more memorable scenes occurs when Piper's character dons the glasses for the first time, and notices that a billboard featuring a smiling model now simply blares the word "OBEY".
With its narrative conceit of the world being an illusion behind which a darker reality exists, They Live can be said to presage The Matrix and its sequels — though Carpenter's film does not indulge in philosophy. Interestingly, a similar premise was featured in an episode of the 1950s television show Lights Out titled "The Martian Eyes", in which Burgess Meredith plays a man whose sunglasses allow him to see Martians who have disguised themselves as Earthmen.
As with many of Carpenter's excursions into genre filmmaking, They Live was critically panned upon its release and fared poorly at the box office, only to develop a more favorable reputation in later years on home video. A special edition DVD was released in 2003.