After discovering that a strange planet is hurtling directly towards Danville, Phineas and Ferb set out to avert a disaster, while Buford looks forward to making contact with its alien race. Meanwhile, Dr. Doofenshmirtz hopes to steal the world's largest ball of twine. / When one of Dr. Doofenshmirtz's "-inators" zaps him and Agent P into the middle of nowhere, they must embark on a comical journey filled with twists and turns to return home.