A pod arrives aboard Red Dwarf containing a genetic mutant which can change itself into any shape whatsoever. It appears to Lister in it's true form, bringing him to the height of his terror, and then sucking his fear right out of him. While they are searching for it, Cat is chased by his own heat-seeking bazookoid balls, and eventually manages evade them and lock them in a room. The Polymorph gets the Cat and takes away his vanity by appearing as a beautiful woman and flattering him. It then appears as Rimmer and blames Kryten for the Cat being attacked, thereby taking away Kryten's guilt. Later, when the three get back it appears as Rimmer's mother, pretending to have slept with Lister, angering Rimmer so much that it feeds off him also.. .
The gang now have very different personalities: we have Rimmer, a "wannabe" hippy, (T-shirt saying "Give quiche a chance"), Lister with nerves of steel and willing to sacrifice his life to kill it, Kryten with no sense of loyalty or guilt, and the Cat, a bum. They continue their search for the Polymorph and suddenly it comes up and attacks from behind. Luckily, an automatic door opens, releasing the bazookoid balls that were chasing the cat. The crew duck and the polymorph is destroyed. All the crew get their emotions back and they are free from the polymorph. Or so it may seem...moreless