Run, Candace, Run, Last Train to Bustville

Phineas and Ferb's newest invention is a pair of boots that make the wearer extraordinarily fast. Candace decides to wear them so that she can be in two places at once; at Jeremy's family picnic, where she runs into Mrs. Johnson, and also at the library where she promised Mom she would read to the kids. Meanwhile, Dr. Doofenshmirtz's building is put up for sale so he tries to convince a prospective buyer, Annabelle, who turns out to be a long lost relative of the Johnson family, that it is not worth buying.
While visiting their grandparents, the kids decide to create and race a giant hot air balloon. Meanwhile, Candace is inspired by 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.