- Directors: Ridley Scott
- Producers: Gordon Carroll, David Giler, Walter Hill
- Writers: Story, Dan O Bannon, Ronald Shusset, Screenplay, Dan O Bannon, David Giler, Walter Hill
- Genres: Horror, Sci-Fi, Thriller
- Actors: Tom Skerritt, Sigourney Weaver, Veronica Cartwright, Harry Dean Stanton, John Hurt, Ian Holm, Yaphet Kotto
The commercial towing spaceship Nostromo is on a return trip from Thedus to Earth, hauling a refinery and twenty million tons of mineral ore and carrying its seven-member crew in stasis. Upon receiving a transmission of unknown origin from a nearby planetoid, the ship’s computer awakens the crew. Acting on orders from their corporate employers, the crew lands the Nostromo on the planetoid, resulting in some damage to the ship. Captain Dallas (Tom Skerritt), Executive Officer Kane (John Hurt), and Navigator Lambert (Veronica Cartwright) set out to investigate the signal’s source while Warrant Officer Ripley (Sigourney Weaver), Science Officer Ash (Ian Holm), and Engineers Brett (Harry Dean Stanton) and Parker (Yaphet Kotto) stay behind to monitor their progress and make repairs.
Dallas, Kane, and Lambert discover that the signal is coming from a derelict alien spacecraft. Inside it they find the remains of a large alien creature whose ribs appear to have been bent outward from the inside. Ripley, meanwhile, determines that the signal transmission is some type of warning. Kane discovers a chamber containing numerous eggs, one of which releases a creature that attaches itself to his face. Dallas and Lambert carry the unconscious Kane back to the Nostromo, where Ash allows them inside against Ripley’s orders to follow the ship’s quarantine protocol. They unsuccessfully attempt to remove the creature from Kane’s face, discovering that its blood is a potent acid. Eventually the creature detaches on its own and is found dead. With the ship repaired, the crew resume their trip back to Earth.
As she prepares to enter stasis Ripley discovers that the Alien is aboard the shuttle. She puts on a space suit and opens the hatch, causing explosive decompression which forces the Alien to the open doorway. She shoots it with a grappling gun which pushes it out, but the gun is caught in the closing door and the Alien is tethered to the shuttle. It attempts to crawl into one of the engines, but Ripley activates them and blasts the Alien into space. The film ends with Ripley and Jones entering stasis for the return trip to Earth.