During a nighttime military operation in a remote desert region, a U.S. Special Forces team led by Sergeant Kelly is ambushed. In the middle of the firefight, the soldiers are mysteriously abducted and vanish from the battlefield. They awaken, disoriented and confined inside translucent stasis pods, aboard a massive, dimly lit alien spacecraft.
As the soldiers recover, the stasis pods suddenly dissolve, expelling them. Exploring their surroundings, the team finds skinned human corpses and unfamiliar weapons and technology. They are soon attacked by alien creatures—tall, eyeless humanoids with armored skin, sharp claws, and energy-based shields. The soldiers fight their way through the corridors using their remaining weapons and scavenged alien gear.
The group encounters Ravi, a young Russian woman. Wary of the team, she explains that the ship collects humans to be processed as food. She joins the group and leads them through lesser-traveled maintenance tunnels. After a series of battles, she trusts them enough to tell them of a safe room. The team follows, eventually dropping down a vent into a pool of blood filled with remains of humans. Arguing and panic ensues before another survivor named Anya, Ravi’s mother, appears and rescues them.
Anya tells the soldiers that she has survived for twenty to thirty years in the ship, and that she has a plan to destroy the aliens communication array with explosives to prevent reinforcements. But to do so, a distraction is needed, so Kelly agrees to draw as many of the aliens away as he can. Although successful at first, one of the aliens, Scars, discerns their plan when the team shows up on a motion sensor, which enables him and other aliens to track them. With the group decimated down to Kelly, Ravi, a solider named Nash and herself, Anya sacrifices herself in a final stand by detonating charges that destroy most of the pursuing aliens.
The remaining fugitives reach a hatch leading outside, only for Nash to get killed by Scars, the only survivor of his crew. After luring Scars into an open hatch and closing it on him, cutting him in half, Kelly finds Ravi looking upwards at an orange glow. Upon climbing some debris, they look out in stunned silence on the destroyed city of Paris.