A Predator ship crash-lands on Earth. U.S. Army Ranger sniper Quinn McKenna and his team are attacked by the Predator while on a hostage retrieval mission. McKenna incapacitates the Predator and has parts of its armor sent off by mail to prove the existence of extraterrestrial life. At the behest of government agent Will Traeger, McKenna is captured and held for examination. Traeger also takes the Predator to a lab for experimentation and observation, recruiting evolutionary biologist Casey Bracket to study it. Bracket discovers that the Predator contains human DNA as part of his genetic makeup and her primary task is to discover how. The Predator awakens, breaks out of its restraints and kills both the lab workers and armed guards, but spares Bracket, the only unarmed person, before escaping. McKenna is bussed off with a group of other government captives, including former Marines "Nebraska" Williams, Coyle, Baxley, Lynch, and Army helicopter pilot Nettles. Witnessing the Predator's escape from the lab, they hijack the bus. Taking Bracket with them, they head over to McKenna's estranged wife, Emily, where he expects to find the Predator armor he mailed off. However, Rory, McKenna's autistic son, has gone trick-or-treating in the armor in hopes of avoiding detection from bullies. McKenna and the others find his son just in time to stop a pair of Predator hounds from ambushing the boy. McKenna kills one of them by shooting a grenade into its mouth, causing it to explode. Nebraska unintentionally lobotomizes the other dog after shooting it in the head. The Predator chases them into a nearby school, and they start to give the Predator's armor back when another, much larger and more powerful Predator arrives and engages the first in combat. The group flee, and the second Predator kills the first before setting out to retrieve the lost technology.