Premise: Phineas Flynn and his stepbrother, Ferb Fletcher, are determined to make every day of their summer vacation fun. They try building a full-scale roller coaster, becoming musicians, building a backyard beach, and traveling back in time to meet dinosaurs. Their family pet, Perry the Platypus, doubles as a secret agent and battles evil. Meanwhile, older sister Candace is tattling on them to Mom and Dad, though she can never seem to catch them in the act.
S04, E21 (First Aired: Oct. 5, 2013)
Candace accidentally conjures up a spell; Doofenshmirtz encounters a mythological, giant floating baby head; an evil platypus is set on destroying the town.
(First Aired: Oct. 11, 2013)
Doofenshmirtz inherits a castle in Druselstein, so Vanessa moves her Halloween party to the new place; Doofenshmirtz develops a theory that enlarging small, cute animals into giant beasts will help him take over the Tri-State area.