Phineas and Ferb enter the Swamp Oil 500 after upgrading mom's car and turning it into race car 42. Meanwhile, Dr. Doofenshmirtz tries to deflate everything in the Tri-State Area from his blimp. --- Phineas and Ferb build a huge paradise of a beach in their backyard on the hottest day of the year. Meanwhile, Agent P tries to stop Dr. Doofenshmirtz from stealing all lawn gnomes in the Tri-State Area in revenge for having to dress as one in his youth.