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 commanded by Capt. Rick retrieves the pod and opens it at a defunct space station, which revives Charlie. But while Rick waits for the Terracorps corporation to arrive and take the eggs, they hatch, placing Charlie and the whole crew in mortal danger.