Stimpy creates a cloning liquid in his lab, and it falls into Ren's hands.

Ren and Stimpy are two starving peasants in a fairy-tale world, so Stimpy tries to wrangle some wheels of magic singing cheese from the village idiot by besting him in a contest of stupidity.

Ren can't stand Stimpy anymore, so he sends Stimpy on a one-way ticket out of town. Then they are hit by a bus and get united (literally) in a cheap hospital.

When Ren and Stimpy find out they are about to be cancelled, Ren comments that they'll do anything to keep the show on going, so the producer makes "a twist in chemistry" by making Stimpy the skinny jerk and Ren as the fat idiot.