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!

When an early end to their daily project causes Phineas and Ferb to mistake an egg for Perry's, the boys use all their technological knowhow to help hatch the new part of the family. However Candace has different plans for the egg, as a nature show brings her to be the one to convince Phineas and Ferb that the newborn will need a real mother. Meanwhile, Doofenshmirtz is doing all he can to convince Perry that his latest scheme really is evil.