When Phineas and Ferb get inspired by Candace's dessert club to create the biggest piece of gelatin ever, even Jenny and Stacy want to join in. Meanwhile, Doofenshmirtz has a horrific plan, to turn Perry evil!

Fed up with her brother's inventions always disappearing, Candace enlists the help of everyone in the neighborhood to build and watch a big and obvious invention, that they might finally see exactly what happens to everything. Meanwhile, is it mime? No, it's Doofenshmirtz' new Invisibility Ray.