When Ferb's cousins visit from England and challenge him to a soccer match, he and Phineas warp the walls of physics and build a high tech 3D stadium. Meanwhile, convinced that her relationship with Jeremy depends on her being more proper, Candace enlists the help of Ferb's British cousin, Eliza, to teach her the rules of etiquette. Back at Doofenshmirtz Evil Inc., Dr. Doofenshmirtz is sick in couch but forces himself to set off his \"If-A-Tree-Fell-in-the-Forest-Inator\", which causes any tree that falls to say his name.

Potato gremlins appear all over town when Phineas and Ferb clone a potato chip from Buford and it mixes with his DNA; Doofenshmirtz tries to summon the Spartan army with his historical army retrieve-inator.

Thinking it would be cool to be part of an ant society, Phineas and Ferb create and infiltrate the Antius Maximus, a massive ant farm filled with giant ants. Suspecting that the boys are up to something, Candace accidentally drenches herself in the ant pheromones and follows them inside. Meanwhile, Doofenshmirtz feels tired and lethargic after eating turkey and decides to create a Turkey-Inator that will create a sleeping epidemic in Danville by turning things into giant irresistible turkeys.

Baljeet announces that he is no longer Buford's nerd, and Buford is heartbroken.

Phineas and Ferb create their own flying saucer to help solve the mystery of a recent rash of crop circles. Meanwhile, Candace tries to give up her tattling habit by taking a "me" day, and across town, Dr. Doofenshmirtz challenges the local pizzeria's "37 Minutes or it's Free" rule by using his "dough-blow-inator" to generate a powerful current of air to hold the pizza dough aloft indefinitely.

The guys help their dad unearth a missing piece of Danville history; Doofenshmirtz tries to make himself younger to win a children's film festival.

Phineas and Ferb create their own TV shows and commercials.