Introduction:The Nostromo, an interstellar commercial towing-vehicle with
a crew of seven, has set out from Thedus to Earth, hauling twenty-million tons
of mineral ore. At the start of the film, the ship’s computer MU-TH-R 182,
simply called “Mother” by the crew, receives an apparently unidentifiable signal
from a moon orbiting a nearby planet, while monitoring the ship’s operations.
The ship drops out of hyperspace, and “Mother” wakes the crew from stasis, so
they can investigate the signal’s origin. With the ore and mining facilities
left in orbit, the tug portion of the Nostromo lands on the moon, suffering
serious damage during the rough landing.

Captain Dallas (Tom Skerritt), Kane (John Hurt) and Lambert (Veronica
Cartwright) leave the ship to investigate the signal. They soon discover a
derelict spacecraft of unknown origin. The group enters the craft, finding the
pilot’s desiccated remains (see Space Jockey). Kane descends into a chamber
beneath the pilot, discovering thousands of leathery eggs protected by a
forcefield. One of the eggs opens, a lifeform inside leaps out, somehow breaks
through the visor of Kane’s spacesuit and attaches itself to his face. Dallas
and Lambert carry the unconscious Kane back to the Nostromo. Ripley (Sigourney
Weaver), the commanding officer in Dallas’s absence, refuses to let them back
onboard, citing quarantine protocol. However, Science Officer Ash (Ian Holm)
disregards Ripley’s decision and lets them in. In the ship’s infirmary Dallas
and Ash attempt to remove the creature from Kane’s face, but they discover they
cannot remove it by force without harming Kane. When they try to cut off one of
its digits, the alien’s highly acidic blood sprays on the floor and burns its
way through several decks of the spaceship. Due to this lethal defense mechanism,
the crew cease from further attempts at removal. Eventually the creature
detaches from Kane’s face on its own, and the crew find it dead. Kane wakes up,
seemingly unharmed.