A nameless unemployed drifter referred to as "Nada" (Roddy Piper) finds construction work in Los Angeles, and befriends fellow worker Frank Armitage (Keith David), who leads him to a local shantytown soup kitchen. There, Nada notices strange activity around the church; a blind preacher rouses others to awaken, a police helicopter scouts them overhead, and a homeless drifter (George Buck Flower) complains when the TV signal is continually interrupted by a bearded man informing others about those in power. Nada discovers the church is a front: the choir is actually an audio recording next to scientific apparatus, while cardboard boxes fill the room. Nada finds another box hidden in the wall but escapes when the preacher catches him. At night, police bulldoze the shantytown and attack its fleeing inhabitants. Nada returns in the morning to find the church empty, but procures the untouched hidden box. At an alleyway he opens it to find it contains black sunglasses and takes a pair.
Nada discovers the sunglasses are special; looking through them he sees the reality of the bleak world. The media and advertising actually contain totalitarian commands of obedience and conformity in consumerism, to control an unwitting human population. Many with authority and wealth are actually humanoid aliens with grotesque skull-like faces. At a store Nada confronts an alien woman, who then speaks into a wristwatch notifying others about him. Two alien police officers apprehend Nada but he kills them, taking their guns and going on a shooting spree against aliens in a bank, while one vanishes using its wristwatch. Nada escapes, destroying an alien flying camera and taking Cable 54 assistant director Holly Thompson (Meg Foster) hostage. At her hill-top home, Nada tries convincing her of the truth while suffering a headache from the glasses. Instead, Holly knocks him through her window and calls the police. Nada tumbles down and escapes, leaving his belongings behind.
Nada returns to the alleyway and saves the sunglasses box from a garbage truck. Frank meets him to hand him his wage, but tells Nada, now a wanted man, to stay away. Nada engages Frank in a long fistfight to make him wear the glasses. After he finally does and sees the truth, the two rent a hotel to discuss their predicament. Gilbert (Peter Jason), a member of the shantytown, notifies them about a secret meeting with other activists. There, Nada and Frank are given updated contact lenses to replace their glasses. They learn from the bearded man's broadcast that the aliens control Earth as their third world, depleting its resources and causing global warming before moving onto other planets. The aliens use a signal to camouflage themselves; destroying its source will allow everyone on Earth to see their true form. Frank is given an alien wristwatch, a complex radio and teleportation device. Holly appears, apparently joining the cause before apologizing to Nada. However the police attack the meeting, killing anyone in sight, while Nada and Frank are cornered fighting their way out. Frank accidentally opens a temporary portal by throwing the watch, through which the two jump into a network of underground passages.
The two find the aliens in a grand hall celebrating with their elite human collaborators. The homeless drifter from earlier, now a well-dressed collaborator, believes the two to be collaborators as well. He takes them on a tour of the passages, revealed to link the alien society, including a space travel port. A further passage leads to the basement of Cable 54 station, the source of the signal. The two then launch an attack through the building to find the broadcaster on the roof, before meeting Holly and taking her along. As Nada climbs to the signal broadcaster, disguised as a satellite dish, Holly kills Frank. Revealed to be a collaborator, she takes aim at Nada and persuades him to stop as an alien police helicopter hovers overhead. Nada complies by dropping his weapon, but then retrieves a hidden pistol from his sleeve and kills her. He then shoots and destroys the broadcaster before being killed by the aliens, giving them the finger as his last gesture. With the signal destroyed, humans discover the aliens in their midst.
Everything is Opening
