 While Rimmer and Kryten find the remains of a mutated human with three heads, Cat accidentally activates a machine that turns Lister into a chicken.When the others arrive, Kryten determines that the ship's crew were researching DNA modifications and that the machine Cat used can rewrite the DNA of anything with organic matter.When an attempt to reverse the effect on Lister changes him into a hamster, Cat repeats the actions he did to change him.