Phineas Flynn and his stepbrother, Ferb Fletcher, make every day of their summer vacation an adventure. From ambitious new inventions to helping those in need, they always get into something fun. Meanwhile, across town, the wannabe-evil scientist Dr. Doofenshmirtz continually attempts to take over the Tri-State Area with his various "inator" devices, and Perry the Platypus, the boys' pet and a secret agent, consistently foils his plans on behalf of the O.W.C.A and his commanding officer, Major Monogram.