The boys are inspired to make gelatin in their pool after Candace tells them to do something with their dessert. But, when Dr. Doofenshmirtz demonstrates his newest invention, the "Turn Everything Evil-inator", it literally brings the gelatin to life.
The family and Stacy visit London, where Stacy and Candace investigate the boys' newest scheme like how Sherlock Holmes would. Meanwhile, Perry collaborates with a British spy, Double 0-0 or 00 0, to foil Dr. Doofenshmirtz's plan to move Big Ben to Danville as an alternative to reading his tiny watch.