Zula Hendricks tracks down Amanda Ripley on Earth in order to enlist her help in her fight against the Aliens and Weyland-Yutani. Using the unlicensed colony ship Gaspar as cover, Zula, Amanda and Davis launch their ship, the Celestial, from Mexico City to a classified Company blacksite.
After nine days in hypersleep they arrive and find the Gaspar is there as well. Eleven hundred colonists on the Gaspar are off loaded to the Company installation and exposed to a gas by combat androids, then loaded back onto their ship and sent into a decaying orbit toward the moon below.
Amanda and Zula fight off the droids on the installation while Davis arms a nuclear failsafe. They get separated from the station and end up falling to the moon below in a hex-ball, using the Gaspar to help shield their entry into the atmosphere.
Arming themselves from the now abandoned Gaspar, they only manage to find one survivor of the Company’s experiments – a teenage boy named Alec Brand – and evacuate him aboard the Celestial, piloted by Davis. With the nuke in orbit about to detonate, Amanda and Zula tell him to leave with Brand as he is the evidence of Weyland-Yutani’s crimes. Holding off an Alien horde and low on ammo, the explosion hits the moon. Amanda and Zula take shelter under the hex ball.
Alec Brand is returned to Luna Base and his testimony condemns the Company.
Weyland-Yutani is charged for their actions and is punished with massive fines. In the years that follow they pay lobbyists to try to get the laws they broke changed and make plans to return to the blacksite.
After about 3 weeks on the moon, Davis returns in the Celestial to rescue Amanda and Zula them, having survived thanks to the moons unique biome that thrives on radiation. The moon itself however, thanks to the force of the nuke, begins to break up.
Brand eventually joins the Colonial Marines.
Colonial Marine Alec Brand is assigned to Deep Space Recon and joins Amanda Ripley and Zula Hendricks, whom he had believed dead, at the Company blacksite he was rescued from five years earlier.
The moon they’d fled is the final stages of breaking up, but in the preceding years Alien biological material has been falling to the super-Earth sized planet below. They monitor Xenomorph activity from orbit and note they are migrating northward.
Hendricks, Ripley and Brand, with Davis flying in a drone, lead a squad to the point of migration and find three Queens in an underground nest. Fighting back scores of Aliens, Brand manages to collapse the cavern on the creatures, thus denying Weyland-Yutani specimens and ensuring the biome of the planet is protected from private hands. Towns like El Hoyo where Brand grew up (which was abandoned five years earlier due to climate and pollution problems) can now be rehabilitated.