Mankind should battle to outlive as Earth is invaded by hostile UFOs bent on destroying the planet. Because the epic battle wages on, astronauts sneak aboard the mothership the place they uncover a portal to the aliens' residence world. They handle to alert Earth earlier than they're brutally murdered. Left with no different alternative, Earth sends an elite army workforce of science and fight specialists by way of the portal the place they try to cease the invasion from the within out.