Okay so I am absolutely hooked on the whole idea of the third Phineas and Ferb movie. I have no clue what its going to be like but my mind has been running with concepts. Ive come up with an AU. Basically a what if they never met!
Phineas is a quiet kid. An outcast. He's all ideas and imagination with nowhere to go. His ideas are deemed to reckless, to unfinished, too much imagination. So he learned to be quieter. He doesn't have friends. He's got a massive crush on the prettiest most confident girl in school but she barely knows he exists, probably only knows him as the weird idea kid. He goes to school, and comes home to his mom and sister arguing because they don't understand each other. His room is too big. it feels like something is always missing.
Ferb is a boy genius. If you give him blueprints or instructions, he can do just about anything. (Don't ask him to come up with something original though.) He keeps up being perfect because that makes it easy for his single dad who does everything and is always tired. He's always praised by teachers, idolized by peers. He wishes he could just be in the background without all the eyes on him. He goes home to his bedroom that feels so small, and pets his platypus Perry who's the only one that really sees him.
One day, Ferb gets a huge opportunity to visit America for a competition. He goes of course, its expected of him. Phineas has been recruited by a teacher to help set up, because no one else volunteered. He accidentally bumps into the boy genius visiting from the UK. And well. Things go from there.