The film begins where the Critters 3 left off, as Charlie McFadden (Don Keith Opper) still in his role as an alien bounty hunter, is about to destroy two Critter eggs. He is suddenly stopped by a hologram message from his alien friend Ug (Terrance Mann), who tells him the eggs are the last two Critters in existence and that it is against an intergalactic law to cause their extinction. Charlie protests that the Critters are too dangerous to keep alive, but he obeys Ug's orders to place the eggs in a preservation capsule that suddenly falls from the sky. As Charlie puts the eggs in the pod, the hatch closes on him and he is launched into space.