The Emperor's New School - Season 2 - Eps 37: Guaca Rules
When Kuzco's class visits the museum, an ancient tablet reveals that Kuzco is not the true heir to the throne, Guaca is! Guaca immediately takes over the palace and starts to treat even Kuzco unfairly. Yzma decides to take advantage of this and trick him into hiring her as his adviser, however none of her old tricks work on Guaca due to his obsession with Kuzco. Then he demands that Malina become his empress or he will build a store over her house. Kuzco and Malina then decide to seek out a special chalice that will reveal the true heir to the throne.
About The Emperor's New School

Title: The Emperor's New School
First Air Date: 2006-01-27
Last Air Date: 2008-11-20
Status: Ended
Rating: 7.3/10 (from 142 votes)
Language: EN
Seasons: 2
Total Episodes: 90
Network: Disney Channel
Genres: Comedy, Kids, Animation, Sci-Fi & Fantasy
Production Companies: Disney Television Animation
Synopsis
It's about Kuzco, a self-centered and spoiled teen who must survive the trials of Incan public school and pass all of his classes so that he can officially become Emperor. His friend Malina keeps his attitude in check, while the evil Yzma (cleverly disguised as Principal Amzy) and her dim-witted sidekick Kronk are out to make sure Kuzco fails.
Cast

Eartha Kitt
Yzma (voice)

Curtis Armstrong
Mr. Moleguaco (voice)

Justin Cowden
Guaca (voice)

Rip Taylor
The Royal Record Keeper (voice)

Shane Baumel
Tipo (voice)

Bob Bergen
Bucky (voice)

J.P. Manoux
Kuzco (voice)

John Goodman
Pacha (voice)

Patrick Warburton
Kronk (voice)

Jessica DiCicco
Malina (voice)