When Ren and Stimpy find out they are about to be cancelled thus breaking the 4th wall again, Ren comments that they'll do anything to keep the show ongoing, so the producer makes a twist in chemistry by making Stimpy the skinny jerk cat and Ren as the fat idiot dog, but Ren starts to realize that this might not be a good idea after all.
There are two versions of this episode. One includes a "pre-credits" scene showing a obese Ren revealing himself on stage to a full house as the film stops. Ren recaps to the audience, in the moment, yet, a flashback, that a series of events led up to this happening to him, for which he was excited about. Ren plays the episode as a flashback leading up to this moment as the title card and credits show.
Ren and Stimpy are revealed to be cartoon actors again in their studio in "Hollywood". They have a meeting with the director, who is the same guy who was Ren's boss in other episodes, who they both have a feeling has only good news. However, this is not the case as the man is violently angry, saying that Ren and Stimpy's ratings are at an all time low, and they will be cancelled. Ren and Stimpy plead with him to find a way to not get cancelled, so he decides on the old "role reversal" scenario. Stimpy will become the "skinny jerk" (Ren), and Ren will be the "fat idiot" (Stimpy). This literally blows Ren's mind, but the director boss tells them if they don't like it, they can be cancelled and fired.
Out of fear, Ren is transported to a hospital called "Fat and Thin Institute for the Stars" where Ren sits in a room with a drink serving machine and monitor. His boss comes on the TV, and Ren argues with him. He reminds Ren bluntly and matter-of-factly that he's in total control, and Ren can again get over it or lose his contract. Ren is forced to drink hundreds of "milkshakes" served by the machine, to which he questions. The director says it's a secret ingredient (it's revealed that Stimpy is being liposuctioned the other room, and his fat is being served to Ren as these "milkshakes"). Intimidated by the director, Ren drinks all the shakes and grows very fat, looking slightly like Jabba the Hut. The director tells Ren to come check out Stimpy. Ren goes to see his friend, and is shocked to find him skinny as a rail with his eyes and nose more pronounced. The director says now that their appearances are down they have to study the lines to learn to be their new personas. Meanwhile, Ren regrets going along with all this, feeling ugly and gross being fat. Stimpy (who Ren has grown slightly jealous of his skinnyness) reassures him it'll be okay. Ren instead goes crazy and tells Stimpy that he'll now be the more loved character, because everybody loves the "fat idiot" who he is now, and Stimpy will be hated as he was before as the "skinny jerk". Ren storms off to go prove it as Stimpy figures out how to play a skinny jerk. At first, Stimpy struggles as he is naturally a innocent, nice guy. But soon, the more he practices the easier it gets and he starts to like it a little, soon screaming Ren's line "Where's my dinner?!" like a raving madman.
Meanwhile, Ren has covered himself in a trench coat and has allowed himself to be on a stage before thousands of people in a theater. Ren says this is for all his "adoring fans", as he removes his coat, revealing his naked, fat body to everyone, screaming "LOVE ME!". The episode freezes, and Ren, once again narrating as he did in the prelogue, summarizes this is what happened. And he has been so looking forward to this moment as now he can be loved by millions as a fat, lovable idiot. The episode resumes. Instead of accepting him, the crowd scolds him and throws rotten tomatoes at him, violently labeling him and rejecting him as "fat", "ugly" and "a freak", breaking Ren's heart. Feeling dejected, alone and miserable, he feels no one else bit Stimpy would understand, being such a kind friend to him. He enters their stage room to ask his buddy for advice and support, but Stimpy turns to Ren to reveal his acting lessons have changed his personality for the worse. Stimpy is even meaner than Ren was as he cusses him out in the same fashion as he used to do to him, accusing him of up to doing "stoo-pid hijinks" instead of waiting on him and telling him how bad his breath stinks. Ren realizes he is doomed, Ren dreads the taping of this new episode that night.
At the stage, the episode of Ren being the fat idiot and Stimpy the skinny jerk is about to be filmed. Everyone is taking their places as Stimpy is more egotistical and blunt than ever, and Ren, meek and depressed as he's ever been take their places on the set as their hotheaded, control freak director watches on with eagle eyes as they being filming the episode before a live audience. Stimpy starts calling Ren "eed-iot" and "stoop-id", barraging out the insults to Ren, who would rather whimper than say his lines. The director calls Ren stupid and orders him to say his line. Ren messes it up, enraging the director as he screams at the "fat slob" to act. As Stimpy says Ren is just trying to make him look bad, as more cameras are shoved down Ren's throat, as the director keeps insulting his clumsiness and cowardice and not reciting his lines properly, all the while the crowd laughs at him mockingly. Ren has finally had enough and screams as loud as he can for everyone to stop, as he begins to insult and attack everyone, picking the director up off the ground and with all his might throwing him at Stimpy, smashing them both into a wall. Ren decides after being mocked, ridiculed and picked on he doesn't care about his acting career anyone, screaming "I QUIT!!!" In utter rage to Stimpy and the director and the entire audience. A brief pause happens, before the crowd lets out a roaring applause at Ren's "performance" which puts him in Variety Magazine as "The Best Performance Ever" as flowers are tossed on stage and confetti fills the theater as Ren celebrates and thanks the crowd. Stimpy and the Director have a change of heart towards Ren, as the boss complements Ren on his performance, telling the fat Chihuahua he's "going places" after receiving an acting award and being hoisted up by everyone, Ren decides to not stay angry and instead looks at the camera with a smile, saying "That's show business!"
- This is the only episode with a black title screen.
- This episode was originally written to be an Adult Party Cartoon/Spümcø episode titled "The Big Switch".
- This is the last episode from Spümcø, and not written by John Kricfalusi.
- This episode marks that season five is the last season of Ren and Stimpy (but not counting Ren and Stimpy "Adult Party Cartoon" since its spin off only ran six episodes).