The film picks up immediately after the events of Alien vs. Predator. A
smaller ship is dispatched from the large clan ship seen in the first film. This
smaller ship contains the “Scar” Predator who had been impregnated by a
Facehugger and killed by an Alien Queen. He gives birth to a chestburster, which
quickly grows into the Predalien and begins a killing spree through the vessel.
A Predator attempts to kill it with his plasma caster and inadvertently shoots a
hole through the ship’s hull, causing it to crash in the forests outside of
Gunnison, Colorado. The Predator who caused the crash landing survives and
activates a distress signal, but is immediately killed by the Predalien. A boy
and his father who are hunting deer see the crash and go to investigate. Both
discover the wreckage of the ship and are shortly impregnated by Facehuggers
that escaped from the damaged vessel.

The distress signal reaches the Predator homeworld, contacting a veteran
hunter. He sees a recording from the Predator’s mask who caused the ship to
crash-land. He watches how the Predalien killed crew members, the ship’s crash,
and knows Aliens are loose on Earth. He prepares his gear, selects a mask, and
departs...