Phineas and Ferb take on a heroic alter-ego as "The Beak" when unexpectedly becoming superheroes with an indestructible suit they built for an extreme skate track. But, when the villain Khaka Peü Peü discovers them, he tries to terrorize the city, and only The Beak can stop him. Meanwhile, Dr. Doofenshmirtz is temporarily given the mayoral post by his brother Roger to prevent him from being blamed for Khaka Peü Peu's presence.