The Nostromo has been floating in space since it was set to self-destruct in an attempt to destroy the Xenomorph that got on board and was later flung into space.
Rain (Cailee Spaeny) and her adopted brother, an artificial person named Andy, dream of basking in the sunlight of a completely terraformed planet called Yvaga.
With hopes of earning a travel pass dashed, Rain and her fellow miners plan to use the Corbelan ship to dock with a decommissioned craft to travel nine lightyears to Yvaga.
This station is broken up into two halves: the Remus, which they're currently on, and the Romulus. Both halves had been dedicated to some form of research project.
After locating the cryo storage room, Tyler and Bjorn (miners) dislodge some tanks, setting off a failsafe system, locking the exit to the room, and raising its temperature.
The frozen experiments have woken up: facehuggers. Tyler, Bjorn, and Andy escape the room, but not before one slips past them and attaches itself to Navarro.
Navarro is freed, but Andy insists that Navarro not be let back onboard the Corbelan. Navarro escapes and Rain, Tyler, and Andy are trapped on the Remus.
Navarro horribly gives birth to a chestbursting Xeno. In her death throes, Navarro's leg kicks the Corbelan's controls and crashing into the Romulus side.
Andy, now having 47 minutes to make it out instead of 36 hours, knows the Xeno wants the door opened to where the others are, but he refuses, leaving Kay to a grisly fate.