You start in a laboratory, growing from a Facehugger into a mature Xenomorph (Specimen 6). After an EMP pulse from the Predator pyramid releases you, you free the queen and establish a hive, harvesting humans and fighting Marines and Predators alike.

While the campaigns are separate, they overlap. For example, the Alien Queen killed in the Marine campaign is the same one the Alien player establishes, and the Abomination (a Predalien) killed by the Predator is the creature created during the Alien campaign.

As a soldier on the USS Marlow , you arrive to investigate a distress call at the Freya’s Prospect colony. After your dropship is destroyed by a Predator, you must navigate the dark, infested colony, rescue trapped Marines (such as Corporal Tequila), and confront Karl Bishop Weyland, who is revealed to be an android.