When Doofinshmirtz unleashes his army of termites to eat all the wood in the tri-state area, Phineas and Ferb use their newfounded love of a cowboy life to herd the stampeding cattle back to the carnival, but with Agent P stuck in a room filling with lava, how will he survive?

Phineas and Ferb create a circus for the neighborhood and Candace becomes the surprise hit of the show while, Doofenshmirtz creates a device to make people's voices higher, making his deeper by comparison.