After killing all the remaining vicious Critter aliens in "Critters 3," bounty hunter Charlie McFadden is shot into space in a capsule with the last two Critter eggs. In the year 2045, a spaceship retrieves the pod and opens it at a defunct space station, which revives Charlie. But while waiting for the Terracorps corporation to arrive and take the eggs, they hatch, placing Charlie and the whole crew in mortal danger.