School’s out for the summer, and stepbrothers Phineas and Ferb decide to make each day an adventure, from building a death-defying rollercoaster to surfing tidal waves to locating Frankenstein’s brain. Meanwhile, the family’s simple-minded pet platypus leads a double life as secret “Agent P” and faces off with the evil Dr. Doofenshmirtz to save the world. (source)