A top-secret government weapons designer is arrested by a clandestine government organization on suspicion of being a clone created by the hostile alien race wanting to take over Earth.
16-year-old Cassie Sullivan tries to survive in a world devastated by the waves of an alien invasion that has already decimated the population and knocked mankind back to the Stone Age.
Special Forces commandos on a mission are abducted mid-operation by a mysterious spacecraft. Upon waking aboard, they find themselves prey to a relentless alien race in a fight for survival.
During the Vietnam War, a recon unit ventures to an isolated jungle valley to uncover the fate of a missing platoon. They soon find themselves in a fight for their lives against an unexpected enemy — prehistoric dinosaurs.