Kermit is skeptical when everyone backstage is terrorized by "the Phantom of the Muppet Show." There turns out to be one, though -- Uncle Deadly, a monster-actor who performed in the theater years ago. After being panned by the critics, he vowed never to perform there again, and not to let anyone else perform either. He warns the Muppets, "Leave or be doomed!"

Muppy, the favorite pet of The Muppet Theatre owner J. P. Grosse, becomes a prima donna when Kermit reluctantly allows him to do a musical number with Scooter. Muppy even gets his own dressing room and star billing, but Kermit draws the line when the dog asks to change the show's title to The Muppy Show. When Muppy locks himself in his dressing room and refuses to perform, Scooter does the number with Fozzie instead.