The crew stumble upon a deserted space ship of non-humanoid origin and Rimmer believes it is an alien ship. They go inside and search the ship where Kryten and Rimmer discover the remains of a three-headed creature. They find a wallet on him with human artifacts such as credit cards, license etc., whereupon Kryten suggests that something has changed his physical form.
Meanwhile, Cat and Lister find a machine with a Star Trek style 'CARRS' computer panel. Cat begins playing with it and accidentally traps Lister in a pink force beam. A deep voice announces that a transmogrification is about to take place. Despite Cat's attempts to get him free, Lister turns into a chicken. Rimmer and Kryten come along and, while Cat is showing what happened to Lister, he traps Kryten in the same beam. He manages to change Lister back to a human, but when he does the same for Kryten, it actually transforms him into a human, rather than just setting him free.
Back on Red Dwarf, Kryten is delighted with his new-found humanity. However he soon starts to tire of it after talking to his spare heads and realising that he has betrayed his kind, and wants to be changed back. They go back aboard the ship and Holly says she thinks she has the computer all figured out. Rimmer decides it would be best if she tried it on something else first.
She tries the process on Lister's curry and turns it into a monster by mistake. After being chased all over the ship, Lister decides the only way to defeat it is to turn him into a superhuman. Holly turns him into something like Robocop, but, inadvertently, tiny -- about 1 1/2' tall! Lister eventually defeats the Curry Monster with a can of lager, which, as he knows, is the only thing that can kill a vindaloo.moreless