The U.S. sends miners to excavate a distant planet. As they return, they unknowingly pick up alien stowaways. The ship loses communication with Earth, and a response team is sent to board the ship. Before dying, the team sends a message saying the ship is infested with aliens. Shortly after, escape pods land on Earth. Aliens exit and begin a human killing spree. The infested ship cannot be shot down, but a second response team manages to board. Now, they must figure out how to self-destruct the ship and rescue any survivors before humanity is completely wiped out.