Professor Von Doofenshmirtz created a giant robotic swan to destroy the Danville World Fair, for some reason. However, he ended getting thwarted by Swerry , who then destroy the giant swan, sending von Doofenshmirtz soaring into the sky. In the end of the episode, Von Doofenshmirtz wasn't seen ever since until over hundred years later, he fell from the sky into the Flynn-Fletchers' backyard at the present timeline, alive but extremely old. Von Doofenshmirtz then wonders how long was he up there.