Phineas and Ferb the Movie: Across the 2nd Dimension

Phineas and Ferb finally discover that Perry, their beloved pet platypus, is a real secret agent who battles the forces of evil every day. They join him on an adventure that blasts them to another dimension, where a truly evil Dr. Doofenshmirtz has taken over an alternate Tri-state Area. When they uncover his plot to travel back to their dimension and take over their own Tri-state Area, the gang and their alter-egos must band together to stop him.