A/N: This is what happens when you watch Bubble Boys/Isabella and the Temple of Sap to many times. You get this. The first half takes place during Bubble Boys, the second half (ten minutes later) takes place during Isabella and the Temple of Sap and the end ties everything up.
A/N 2: This is in the Family/Friendship genre because most of the story revolves around Phineas and Ferb looking for Isabella.
"Hey Ferb, where's Isabella?"
"That's funny. She was supposed to get sap from a Maracanut tree, but…" he checked his watch. "She's not back yet."
"Maybe you should go find them." Baljeet offered.
"Great idea Baljeet! You wanna come along?"
"Ummm…"Baljeet rubbed the back of his neck. "I am not sure. If I rearrange my schedule…"
Phineas stared at his friend a moment. "Well, this could take all day." He slowly tiptoed backwards, whispering to Buford. "Hey, watch Baljeet will you? He looks about ready to crack."
"Awww…do I hafta?"
"Well…you could get the rest of the ingredients to make the bubble—"
"Or study the blueprint." Ferb motioned to his latest schematic.
"Nah. To much work. Besides, blueprints make Buford's head hurt."
"Well, alright then. We'll be back soon. Come on Ferb."
Ferb nodded, following his brother out of the park.
10 minutes later…
"Gee Ferb, where do you think they could be? We've looked everywhere." Ferb shrugged. "I mean, if we don't get the sap, that'll be okay. But I'm worried about Isabella." He coughed. "Uh…the rest of them too."
Ferb smirked, placing a hand on Phineas's shoulder. "We'll find her."
"Yeah…I just don't know where else we could—"
Ferb followed his brother's gaze, jaw dropping at the sight before him. Way off in the distance, a purple hippie van was zooming down a dilapidated rollercoaster track at an alarming rate.
Phineas watched in horror as Isabella climbed out the van's driver side window, sash around her waist. "Oh my gosh! Ferb, we have to help her! We have to help Isabella!"
Ferb calmly shook his head, putting a hand up. "Wait for it…"
"Huh—" His eyes widened as Isabella did a perfect swan dive from the van, snatching the tiny Maracanut tree before swooping up and disappearing back inside. "Wow. Impressive."
Ferb smirked. "And you were worried."
"Me? Worried?" He tapped the tips of fingers together. "Wh-why would I be worried?"
"Because you like her."
"Yeah…" A smile slowly appeared on Phineas's face. He looked at the rollercoaster track; the van was gone. "Well Ferb, we better get back to the park. Buford's probably run Baljeet up the flagpole by now."
"Oh flagpole wedgies are the worst."
Phineas raised an eyebrow. "Yeeaahh…I'll take your word for it."
"Well, that was fun."
"Yeah! Thanks for all the help Isabella. That sap was just what we needed."
"You're welcome." Isabella set the bubble machine in the Flynn-Fletcher garage. "Well, I'm going to head home. Bye Phineas."
"Bye Isabella." He watched her retreating form. "Nice swan dive."
She stopped, looking over her shoulder, a faint blush on her cheeks. "Y-yeah. Thanks. I'll…see you tomorrow."
Ferb walked up, standing beside his brother. He rolled his eyes. "Really Phineas. When it comes to Isabella, you lose all reason."
Phineas merely smiled. "At least I have a lot of it."