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. / Phineas and Ferb have created a device reinforcing the wind and test them on a giant kites in the park. Candace thinks she's finally going to bust when Mom gives her backyard a makeover. Meanwhile, Doofenshmirtz builds a Water-Zalewator to celebrate his girlfriend of the past, who doused him with water, because Heinz she loved, but who then gave him the basket.