Disclaimer: If I owned Phineas and Ferb Montnessa would be a thing, Phinabella would not, and the show would still be going on!
Prologue:
"Ferb! I know what we're going to do today! We're going to rebuild that rollercoaster that we made at the start of this summer, but this time it's going to be a musical! Can you picture it, bro? Random outbursts of song with no discernable music source! You go dig out the blueprints, I'll start ordering parts!" The redhead beside him leapt to his feet in a flurry of movement, off before Ferb could even blink. Climbing to his feet and brushing grass off his high waisted purple shorts, he headed for Blueprint Heaven while his brother put in a call to Blowtorch City. He'd nearly made it to the gate when the rest of the gang walked in. "Hey Dinner bell! Wacha dooin? OUCH!" Buford rubbed his side, staring at the girl in pink with a slightly frightened expression on his face. The addressed boy turned away from the phone with a grin. "We're making a musical rollercoaster!"
"Sorry, only one ride per customer." The Invention was a smashing success. Everyone joined in with the singing, and the rollercoaster was even more accepted than it was the 1st time. As they bid the last of their friends and the top of the tree burst into flames, the angular faced boy turned to him with a wide grin splitting his features. "That was amazing, Ferb! I'd say we should totally do it again, but that would be a bit redundant wouldn't it. Not like any old invention can be turned into a musical! What do you think we should do tomorrow?" Ferb shrugged, taking in the fact that the other boy was practically vibrating. "You're right. Why start wondering now? We might get too excited about it and want to start today! Besides, mom said there was snacks! Let's go!" The boy leapt to his feet, turning back to Ferb when he didn't immediately join him. "You coming, Ferb?" He shook his head. "You go on, Finn. I'm not really hungry right now." The corners of his vision were beginning to fade. The redhead seemed to study him for a moment, then a funny sort of smile curved his lips. "Don't worry, Ferb. We're on our way." The boy didn't move, even as the darkness closed in over Ferb's head, pulling the Brit under.