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.