Oh, There You Are, Perry!, Swiss Family Phineas

Perry the Platypus is reassigned and forced to move to the Quad State area with a new family and battle a new villain, the Regurgitator. During his new assignment, Phineas, Ferb, and Candace put in every effort to find him, hoping he'll return to them.
The family takes a short sail trip out to sea, but a storm causes them to wind up stranded on a remote island. To pass the time, Phineas, Ferb, and Isabella, build a set of treehouses with the most modern conveniences, to Candace's dismay, as she wants to get back home in time to attend Jeremy's party. Meanwhile, Perry the Platypus, who was left behind, must get away from the watchful eye of Baljeet and Buford, so he can go on his mission to stop Dr. Doofenshmirtz's latest plot.