From the Review:
"I had no idea of the existence of Phineas and Ferb until this past spring at a Disney Preview event. This children’s television show follows the lives of two intrepid young boys on their summer vacation. Each day, the boys engage in some brand new scheme (that annoys their sister Candace); usually, there is a secondary plot involving Perry the Platypus (also known as “Agent P”, a member of an all-animal espionage unit) who is out to thwart his nemesis, Dr. Heinz Doofenshmirtz. Inevitably, the two plots collide and a resolution is reached, which usually involves the boys losing their memories of the events, as well as any projects that they have created (to the dismay of Candace, who keeps trying to bust them).
Phineas and Ferb: Across the Second Dimension is based on the movie of the same name. The the game starts off with the normal cast being chased across dimensions by a a more sinister version of Doofenshmirtz from the 2nd dimension. Phineas and Ferb (and company) will have to explore and conquer new worlds to set things right."