Summary
Highlights
Phineas and Ferb decide to trick out their mom's car, turning it into a remote-controlled racing machine for the Swamp Oil 500 race. Candace, their sister, immediately tries to tell their mom, who is playing bridge at a neighbor's house, but her efforts are thwarted by Mrs. Garcia-Shapiro's excessive friendliness and later by the boys' quick thinking and the car's alarm system.
Meanwhile, Perry the Platypus, as Agent P, is tasked with investigating Dr. Doofenshmirtz, who has purchased a giant blimp. Doofenshmirtz reveals his plan to use his 'Deflatinator Ray' to deflate all tires at the Jefferson County Motor Speedway and eventually everything in the Tri-State Area, forcing people to come to him to get things 'flated'. Agent P thwarts his plan, causing the blimp to crash into a TV tower, interrupting the race broadcast.
Candace attempts to show her mom Phineas and Ferb racing with her car on TV. However, her mom struggles with the remote, tuning into a dandruff commercial instead. After several mishaps, Candace finally gets her mom to the racetrack, but before she can show her the car, it has been transformed into a perfectly clean, washed vehicle, much to her mom's delight and Candace's frustration.
Feeling the heat, Phineas and Ferb decide to build a massive backyard beach. Candace is initially dismissive, but when her friends arrive and Jeremy, her crush, shows up with his surfboards, she embraces the idea of hosting a popular beach party.
Agent P discovers Doofenshmirtz's new evil scheme: to destroy all lawn gnomes in the Tri-State Area using his 'Destructinator.' Doofenshmirtz explains his motivation stems from a childhood trauma involving the repossession of his family's lawn gnome.
A surf contest is held at the backyard beach, where Phineas impresses everyone with his extraordinary surfing skills. Candace, crowned "Queen Wahini of the Beach" after winning a limbo contest, enjoys her newfound popularity, especially when Jeremy is present, leading her to forget about busting her brothers.
Candace's mom, concerned by the lack of calls from Candace, decides to come home. Agent P's struggle with Doofenshmirtz's Destructinator inadvertently causes all the water from the backyard beach to drain away, along with all the gnomes. When mom arrives, the beach has vanished, leaving Candace bewildered and struggling to explain the extravagant day to her disbelieving mother.