Hey guys! This is my first fanfic, so I hope you enjoy it! I'll try to post regularly, maybe every week or so! If you want updates, you can check out my tumblr! (Hint: it's the same as my username!) I hope to include other aspects of their life other than romance. I want this to be a fanfic that gives you an idea of where the Phineas and Ferb characters are at 15 (this includes Doofensmirtz and Perry the Platypus. Obviously they're not 15, but Phineas and Ferb are.) Please rate and comment! I want any input you guys have!

Isabella POV

Isabella loved going to that familiar backyard with the gigantic oak tree. The two boys who inhabited it (well, one more than the other) made it even better, what with their incredible exploits every day of the summer. It was even better, now that she hadn't been able to visit it for an entire week because of camporee. It seemed like distance made it even more precious. The backyard wasn't the only thing that she missed in her week of absence. A certain ginger-haired boy loomed in her mind. Sure, he never seemed to notice her flirting (and it was very obvious), but somehow he still managed to make it impossible to give up on him. It was something about the fiery red hair falling into his ocean blue eyes and his adorable smiles and his inventiveness and his adorable optimism and-

And there she went into Phineas-land. It was exactly why she couldn't just give up on him. It wasn't her little crumb cake's fault that he was just so adorable and all kinds of wonderfulness in one person.

It was unfair.

She had to mentally prepare herself to see him. She was currently rehearsing her catchphrase in her head. Whatcha doin'. Whatcha doin'. Whatcha doin'. Yeah, that was it.

It was go-time.

She unlatched the fence in the same way she had been doing since she was eight.

"Hey, Phineas. Whatcha doin'?"

She mentally slapped herself. That was not the way she rehearsed. Oh, he's turning around now. He's so cute. He's opening his mouth. Oh, I'm so glad that he finally got the braces off. He looks so much more adorable. Not that he's not still adorable.

"Hey, Isabella. Ferb and I are just building a life-size replica of the Eiffel Tower out of popsicle sticks," Phineas gestured to the massive wooden structure behind him.

"Oh, wow. It looks just like the real thing! Except, well, you know, made out of popsicle sticks."

"Yeah! That's the idea," he grinned. "You want to see it?"

"Uh, sure!"

Isabella took his open hand. He was suddenly much taller than she was. She remembered when she towered over him (heh!), and she had been worried that it would always be like this, and of course girls can't be the tall ones (well, she didn't believe that anymore).

"-and this is the top!" Phineas turned to her. "So, what do you think?"

Isabella realized that she had zoned out for the entirety of the tour. "Oh, um, it's really cool. Awesome. Great."

"Glad you like it. So, how was camp?"

"Oh, it was great. We sang a lot of songs. Also s'mores. S'mores were good. Uh, Addison sprained her ankle while we were hiking, but that was pretty much it," she responded, scrunching her eyebrows. "Oh, I almost forgot. I got a bunch of patches! And I got some souvenirs for you guys!"

Before Phineas had the chance to respond, a voice called up to him. "How's it going up there, Phineas?"

Isabella narrowed her eyes. "Who's that?"

"Oh, that's right! I forgot to tell you. That's Abby," Phineas waved at the brunette at the bottom of the tower. "She just moved here, and she said she wants to join the Fireside Girls! Isn't that cool?"

"Yeah," Isabella frowned. "Cool."

"You should talk to her. She's really nice."

By that point, a girl with chestnut brown hair and luminescent blue eyes had climbed up to where they stood. "How's it going, guys?"

"Hey, Abby," Phineas waved. "This is Isabella."

Dang it, she's pretty.

"Oh, is this the Isabella that I've heard so much about? I'm so glad to meet you!" she exclaimed, pulling Isabella into a hug. "You're so pretty! Phineas, you didn't tell me she was so pretty!"

Dang it, she's nice.

Phineas smiled at the floor. "Well, yeah, I guess you could- I mean, not that I didn't- I did tell you a lot about her, though."

Isabella managed a tight-lipped smile. "Thanks. Nice to meet you."

An awkward silence fell upon the group. Desperate to fill the silence, Phineas asked, "So, Abby, you mentioned that you wanted to join the Fireside Girls?"

"Yeah! I've always wanted to join them, but there was never a chapter in my town. I mean, I don't have any experience with the Fireside Girls, but it's better to start late than never, right?"

"Yep," Isabella said, popping the 'p'. "So, where'd you come from?"

"Swampy City. Though for a town that has the word 'city' in the name, it's pretty small," Abby laughed. "You guys go to Danville High, right? I think that's where I'm going in August."

"Are you a sophomore, too?"

"Yeah," Abby smiled. "So, I guess we'll be seeing a lot of each other come two weeks."

"Uh huh."

Phineas looked between the two girls, his head tilted and his eyebrow raised. "Why don't we just go down to Ferb?"

Isabella crossed her arms. "Let's do that."

They reached the ground just in time for Buford and Baljeet to enter the backyard. "What's up, nerds?"

Baljeet trailed behind Buford. "I find 'nerd' to be a very derogatory term. I prefer 'studious individual', or perhaps 'overachieving-'"

"Okay, nerd," Buford laughed, putting an emphasis on 'nerd'. He smacked his Tuff Gum.

Baljeet looked at the group that emerged from the tower. "Hey, Isabella's back!"

"Hey, guys," she waved to Baljeet. "How's things been going since I've been gone?"

"It's been okay," Baljeet responded. "Have you been shopping for a scientific calculator yet? I think we're going to need it for AP chemistry."

"No, not yet. I will, though."

Abby looked between them. "You guys are taking AP chem? Wow."

"Yeah," Isabella straightened. "Phineas, Baljeet, and I are all taking it this year."

"Impressive."

A pregnant pause filled the conversation. Ferb blinked.

"Isabella, maybe you could introduce Abby to the other Fireside Girls?"

Not taking her eyes off of Abby, Isabella answered, "Sure, Phineas."

Isabella turned on her heel and stomped towards the fence, with Abby on her heels. The boys watched their retreating forms. Ferb murmured, "Well, this is going to be an interesting year."