While visiting their grandparents, Phineas, Ferb, and friends decide to create and race giant hot air balloons. Meanwhile, Candace misinterprets train engineer Glenda's can-do attitude and decides to "give up" on busting her brothers. On the other side of town, Dr. Doofenshmirtz finds a Dodo bird egg and is convinced that it is a fierce bird-monster that can help him take over the Tri-state area, but discovers the exact opposite when the egg hatches.