Candace brings her plush Ducky to life. Doofenshmirtz encounters a Giant Floating Baby Head. Phineas, Ferb, and their friends confront a horde of evil platypuses.

Annoyed at waiting in really long lines at the return counter, Doofenshmirtz invents a "Back-to-the-Store-inator" to send things back to the store where they came. Meanwhile, Phineas and Ferb stage an extreme batting challenge their friends take place in, and Candace's obsession to bust coincides with her and Jeremy's visit to the Extreme Water Park.

Doof's latest inator changes the way the Earth moves and it is up to Phineas and the gang to save summer.

Isabella unintentionally admits her feelings for Phineas in a letter. Meanwhile, Doof invents an inator to help change his misfortune

In a parallel universe far, far away, Phineas and Ferb are tasked with returning the Death Star plans to the Rebel Alliance before Storm trooper Candace catches up to them. Meanwhile, complications arise when Perry is trapped in carbonite.

After Doofenshmirtz is defeated, a new threat in the 2nd Dimension emerges, leaving it up to Phineas, Ferb, Candace and her resistance fighters to defeat this new foe.