In 2004, a satellite discovers a mysterious heat bloom beneath Bouvetoya, an island located approximately one thousand miles off the coast of Antarctica. Driven by ambition, wealthy industrialist Charles Bishop Weyland utilizes thermal imaging to unveil a pyramid buried 2000 feet beneath the ice. Determined to claim this find for his multinational communications company, Weyland Industries—part of the Weyland Corporation—he assembles a group of specialists, including archaeologists, linguists, drillers, mercenaries, and a guide named Alexa Woods.
As a Predator ship enters Earth's orbit, it deploys a beam that creates a passage through the ice, leading directly to the heat source. Upon reaching an abandoned whaling station, the team descends into the depths below the ice and uncovers the enigmatic pyramid. Their exploration reveals traces of a prehistoric civilization and a sacral chamber laden with human skeletons exhibiting ruptured rib cages.
Unbeknownst to the team, three Predators surface and begin to eliminate all humans above. They venture into the pyramid just as the team accidentally activates it, awakening the Alien Queen from a cryogenic slumber. Soon, she starts producing eggs that hatch face-huggers, which attach themselves to the humans. The subsequent chest-bursters emerge, rapidly evolving into adult Aliens, leading to a brutal conflict among the Predators, Aliens, and the remaining humans.
During this chaotic encounter, two Predators are slain by an Alien, while Weyland meets his end at the hands of the last surviving Predator. This Predator allows both Alexa and archaeologist Sebastian De Rosa a chance to escape. They witness the Predator dispatch a face-hugger and an Alien using a suriken before he unmasks and ceremonially marks himself with the face-hugger's blood. However, another face-hugger soon fastens itself to the now-unmasked Predator.
Deciphering the pyramid's hieroglyphs, Alexa and Sebastian discover the remarkable truth: the Predators have visited Earth for millennia, imparting knowledge on pyramid construction to early human civilizations who revered them as deities. Every 100 years, they engage in a ritual where several humans serve as hosts to create the "ultimate prey" for hunting purposes. If overwhelmed, the Predators are equipped to detonate a self-destruct device to eradicate the Aliens—and themselves.
As the duo realizes the necessity of enabling the Predators to succeed in their hunt to prevent the Aliens from reaching the surface, tragedy strikes when Sebastian is captured by an Alien. This leaves only Alexa and the Predator to combat the growing Alien threat. In a show of solidarity, they activate a self-destruct mechanism to obliterate the pyramid along with the remaining Aliens.
Facing the transformed Alien Queen, Alexa and the Predator, known as Scar, devise a clever strategy, trapping the Queen with a chain and pushing her over a cliff into the ocean depths. Tragically, Scar suffers fatal injuries from the Queen's tail during this encounter.
As a new Predator ship uncloaks, several Predators appear to recover their fallen comrade. An elite Predator honors Alexa by presenting her with a spear weapon in recognition of her bravery as a warrior. As they recede into the cosmos, in a shocking twist, a chest-burster hybrid of Alien and Predator bursts forth from Scar's chest, heralding the events of Aliens vs. Predator: Requiem.
