The expansion takes place in two time periods. The first is roughly five hundred years before the events in Aliens versus Predator 2. The second time period is in 2230, about five weeks before the beginning of the Alien's game in Aliens versus Predator 2.
In both time periods, the game takes place on the planet LV-1201, the site of Aliens versus Predator 2. The expansion revisits the Forward Observation Pods, a group of elevated habitation modules which comprise one of two main human facilities on the planet. Specifically, the player visits Pod 5, which was destroyed prior to the events in Aliens versus Predator 2. The cause of its destruction is revealed in the expansion. The player also visits Zeta Site, a portion of a Xenomorph Hive alluded to in the main game. Zeta Site contains Engineer technology and Yautja ruins.
- The Predalien is the primary Xenomorph playable character. The Predalien starts life as a Facehugger which assaults a Yautja as it enters stasis. The creature birthed from his chest five hundred years later in the human-built Pods, just after the Predator sent a message.
- Major Dunya is the human playable character, a member of the Iron Bears, a private military contractor employed by the Weyland-Yutani Corporation to maintain security on LV-1201. She also plays a small but important role in Aliens versus Predator 2 as a non-playable character. She is engaged to Dimitri, a fellow Iron Bear.
- The Ancient Predator is the main Yautja character. He was the first of his species have a Hunt on LV-1201. He discovered a Hive of Xenomorphs there, and his clan quickly built a facility among the Hive from which to organize their Hunts. When the Hive facility was breached, he was accidentally put into stasis while in the process of restoring the stasis fields in the Egg chambers.
- General Vasili Rykov is the leader of the Iron Bears, who runs an operation smuggling Pilot technology off-planet behind the facility administrator's back. He sends Dunya on a mission to retrieve one such piece of technology at the beginning of her campaign. He plays a crucial role in Aliens versus Predator 2; he is the final enemy faced by the Predator Prince.
- Dimitri is Dunya's fiance, who is endangered by Xenomorphs in the expansion. He appears briefly in Aliens versus Predator 2 before he is killed by Xenomorphs. His death gives Dunya part of her motive for her actions in that game.
- Popov is another henchman. He is killed by Aliens while escorting a Predator Artifact through the Pods.
- Serge is a Russian Iron Bear. He is killed by Aliens while retrieving the Artifact.
- Becker is an Iron Bear. A Texan, he does not agree with some of Rykov's tactics. He is killed by Aliens when retrieving the Artifact.
- Dr. Eisenberg is the head researcher in charge of the LV-1201 facility. He appears in the ending of the game inside Gateway Station.
- Winter is a guard in Pod 5, who was killed by the Predalien.
- Jerry is a Pod 5 guard who was crushed by a sign while smoking. The sign itself reads "No Smoking". A punishment at a right time. The sign might be part of the hatch that the Ancient Predator blew off, allowing him into the pods.
- Dr. Adam Post is a scientist that guides Dunya in the first level. He was studying the relics in the Zeta site (see: Trivia).
The Predalien begins its game as a Facehugger inside the Predators' facility, five hundred years before the Incident. The facility's integrity has just been breached, and the Facehugger must sneak through the complex, seeking a solitary host. If it attacks and subdues a Predator in the sight of others, it will be killed before it can implant its embryo. The Facehugger scurries through vents and under floor grating, using occasional Xenomorph attacks as diversions. Finally, it locates one Predator (the Predator player) attempting to repair a stasis field generator below the facility. It strikes—but both creatures are overcome by the rising stasis field.
The Alien emerges from its host five hundred years later, inside Pod 5. Now a Chestburster, it must find a food source while evading human guards. It makes its way through vents, corridors, and a lavatory to the Pods' morgue, where it feeds and molts into an adult.
When fully-grown, the Predalien stalks and slaughters its way through Pod 5, seeking the Artifact which its host was carrying. Its path back to its host is now blocked by wreckage from the humans' battles with other Xenomorphs, so the Predalien must find an alternate route. It cuts through the botanical labs and nears the Artifact when sirens start going off—the Pod's supports are going to be detonated. The Alien abandons the Artifact in order to save its own life. It fights through a small army of combat synthetics and armored Exosuits, finally escaping through a vent near the pod's generator. It flees with several other Aliens along a support girder just before the supports are destroyed.
Dunya's game begins five weeks before the Incident in Aliens versus Predator 2. She is spending some quality time with her fiance Dimitri when they are interrupted by a call from their mutual superior officer, General Rykov. Rykov asks to meet with Dunya immediately, explaining that they have "found a buyer." When they meet, Rykov explains that Dunya is to retrieve an Artifact discovered during a synthetic-team exploration of Zeta Site. The synthetics were quickly destroyed, but they transmitted information about the Artifact back to Rykov. Doctor Post, a scientist in Rykov's employ provides Dunya with a "worm device," designed to hack into Pilot technology and shut down systems indiscriminately so that she can retrieve the Artifact.
Dunya, Serge, and Decker (two other Iron Bears) infiltrate Zeta Site while the Weyland-Yutani guards have been conveniently incapacitated. They descend to the Hive, where Xenomorphs overwhelm the other two—Dunya is the only survivor. She runs through the Hive, scavenging supplies from the destroyed synthetic expedition. When she reaches the Artifact Chamber, the Xenomorphs pursuing her stop dead in their tracks, watching warily. Dunya reports the situation back to Rykov, then installs the worm device. After some time, the Pilot technology around her starts to fail and collapse, blocking her entrance route.
Finally, the Artifact itself shuts down, allowing Dunya to retrieve it. She does so and is immediately accosted by Aliens. She escapes by clambering over the ruins to the abandoned Predator facility. She fights her way through dozens of Aliens and cunningly-placed Eggs to the surface, then across a series of narrow, bridge-like formations spanning a series of rocky hills. She finally reaches a waiting APC, which takes her back to the Pods.
Later, at the Pods, Rykov informs Dunya that Xenomorphs have infiltrated the Pod and orders Dunya to retrieve the Artifact from storage. Dunya goes to secure the Artifact, arriving just in time to see the Predator making off with it. Rykov, having encountered Predators before, warns her to abandon the Artifact and evacuate the Pod. She arrives at the main elevator, but learns that her fiance Dimitri went to seal the breach which allowed the xenomorphs entry, and he has not been heard from since. Dunya tells the others to evacuate the Pod, insisting that she will keep the cargo area clear until her fiance returns. Using a mounted minigun and a few automated sentries, she does just that. She and Dimitri evacuate the lift, and Rykov detonates the supports keeping Pod 5 attached to the rest of the Pods. Pod 5 crashes to the valley floor below.
Roughly five hundred years before the Incident of Aliens versus Predator 2, a Predator spacecraft encounters the planet LV-1201, which was previously unknown to them. A lone Predator is sent out to hunt game. He encounters a verdant world, full of dangerous prey including a carnivorous, moose-like creature (Buhlagh), a hulking, bipedal reptile capable of disguising itself as part of the terrain (Chameleons), and a wormlike organism which attacks from underground (Tentacle). Quickly, however, the Predator discovers more dangerous prey: Xenomorphs. The Predator follows them to their Hive, through ancient Pilot ruins, where he discovers and activates an ancient Artifact which has the power to keep Xenomorphs at bay.
Eight months later, the Predators have built a sort of hunting lodge or base camp around the Artifact from which to organize hunts deeper into the Hive. The player's Predator descends, with some companions, deeper into the Hive, in search of the Xenomorph Queen. However, an alarm from the facility cuts their Hunt short. The Predators return to the facility to find it overrun by Xenomorphs; the Artifact has been powered down. The Predator fights through hordes of Xenomorphs, restores power to the Artifact, and then attempts to restore power to Pilot-built stasis fields keeping bays of Xenomorph Eggs from hatching. While manually repairing one field generator, the Predator is surprised by a Facehugger—and both are caught in the newly-activated field.
The Predator awakens five hundred years later, when the field is deactivated. He recovers his Bio-Mask and makes his way to the now-ruined Artifact Chamber, where Dunya is making off with the Artifact. He pursues her through the infested ruins of the Predator facility. Finally, he tracks her to the Pods. He infiltrates Pod 5, inadvertently allowing hundreds of Xenomorphs inside with him. He hacks into the human systems to learn the location of the Artifact, which he retrieves. He then breaks into a communications room and transmits a signal to his fellow Predators in the Nodus Secundus system, nine weeks away. Presumably, this transmission is the reason for the Predators' visit in Aliens versus Predator 2. Immediately after sending the transmission, the Predator laughs to his death when the Alien Chestburster incubating inside him bursts from his ribcage. However, the signal was caught by the Prince Predator and his clan, who will Hunt during the Incident.
Primal Hunt was released to extend Aliens versus Predator 2 (developed by Third Law Entertainment). The pack included several new weapons (dual pistols and sentry guns for human players; energy flechette for Predator players), new indigenous wildlife and new multiplayer maps. Its single player campaign also tied up several loose ends in the story of Aliens versus Predator 2 (including the identity and nature of the Artifact sought by the corporates in Aliens versus Predator 2). However, factors such as the shortness of the single player campaign, and the sometimes clumsy nature of the pack's additions limited its appeal.
- The first two levels of the Predator Campaign (Hunt and Stasis), along with the first level of the Predalien's Campaign (New Hosts), occur five-hundred years before the events of Aliens versus Predator 2. As such, the year would be 1730 by human standards.
- Although Dr. Post first appeared in this game, an Adam Post was mentioned in the game. It is likely that Dr. Post was Adam, as he is mentioned to be studying Zeta Site's relics.
- The Hacking Tool was removed from the expansion pack, as players were unable to use it.