Disclaimer: I don't own Phineas and Ferb or Hey Arnold.
"What should we do today Ferb?" Phineas wondered and Ferb only shrugged.
"What about a car that runs on solar power?"Ferb suggested.
"That's a thought."
"What about a computer game?"
"Possibly, but I think I like the solar power car idea. Ferb, I know what we're going to do today."
Once they were ready to build the car, Isabella went over to them. "Hey Phineas. Whatcha doin'?"
"We're going to build a car." Phineas replied.
"Didn't you already do that?"
"Yes, yes we did. This time we are going to build a car that runs on solar power.
"Whatcha doin?" Buford asked them after he and Baljeet entered the backyard.
"Hey, that's my line." Isabella complained.
"Did you hear?"
"What?"
"A bunch of new kids have moved into the neighborhood. I have already met a few of them and invited them to come."
"I'm still hungry." Harold groaned.
"This is Harold."
The backdoor opened and slammed closed. "Alright. Who ate this birthday cake? I baked a cake for Jeremy's birthday party and set it out to cool while I get everything together for the party. When I came back, it was gone."
"It was me. I'm guilty… MOMMY!" Harold screamed and rushed off.
"What are you doing?" Candace demanded, seeing what Phineas and Ferb were doing.
"We're building a car that runs on solar power." Phineas replied.
"You guys are so busted. I'm telling mom. By the way, where's Perry?"
"Where's Abner?" Arnold wondered.
Perry puts on his fedora and taps a brick of the outside of the house, revealing a secret passageway. Abner follows him.
"Agent P… Wait. Who is that pig? I don't recognize him." Major Monogram asked suspiciously.
Perry took Abner's collar off of him and held it up for Major Monogram to see.
"It looks like we have a new agent. We'll call you Agent A. Anyway Dr. Doofenshmirtz has bought ten cans of fishing worms and a fishing rod. Go see what he is up to… Oh and Agent A, welcome to our organization. Here is your fedora." They solute Major Monogram and leave.
"Arnold, Gerald, or Eugene, could one of you pass me that hammer?" Phineas asked.
"Sure." Eugene picked up the hammer, and when he was about to hand it to Phineas, he tripped over a rock. The hammer slipped out of his hand and popped one of the front tires of the car.
Perry and Abner are outside Dr. Doofenshmirtz's house.
"Dad." Vanessa mumbled as she was fixing to leave.
"Yes?" Doofenshmirtz wondered.
"Have you ever thought about opening the door for Perry. I mean, seriously."
"Welcome him in?! But Vanessa."
"You know you should."
Doofenshmirtz sighed as he reached for the door handle. He opened the door and Perry and Abner enter. "Who's that?" He pointed at Abner. Perry did the same thing he did to Major Monogram. "Abner the pig." Doofenshmirtz took out a control with only one button. He pressed the button and trapped Perry and Abner. "Luckily that trap was big enough for the both of you. Now to explain my plan. You may be wondering why I have all these worms and a fishing rod. You are also probably wondering what this has to do with anything. Well, first of all it has to do with my brother Roger. When we were kids, there was a fishing competition and it was between the two of us. He somehow caught a large fish. I never caught a single fish. Our parents congratulated him and since then, he mocked me. Today he will be in another competition and I really want to get back at him. " He explained.
"The car is now finished." Phineas sighed, relieved .
"Want to play some baseball?" Gerald asked.
"Sure."
"Phineas. You were the first to bat and got all strikes." Helga made fun of Phineas.
Arnold was up to bat.
"Hey Arnold. Where are your diapers? Did you leave them at home?" Herald taunted him.
"Just throw the ball." Arnold mumbled.
"So Stacy. You won't believe what…" Candace paused as she noticed a baseball crash through one of the windows and into the second cake, leaving her covered with icing. "I'll call you back." She screamed, "PHINEAS AND FERB!" She glanced outside and noticed the car Phineas and Ferb built, but they weren't there. They're so busted.
"Mom, Mom, Mom!" Candace shouted at her mom through the phone.
"What is it now Candace?"
"Phineas and Ferb built a car in the backyard."
"Candace. Situations like this have happened before. You tell me Phineas and Ferb have built something, call me to tell me about it. I come home and there is nothing there."
"But Mom, they have built a car in the backyard."
"Fine. I'll come home right now."
Arnold was up to bat again and Ferb was the pitcher.
"Hey Ar…" Harold was trying to taunt him again, only to have the baseball slam into him.
Doofenshmirtz picked up his fishing rod and bumped into one of his inators. It made his rod larger. He tried to pick it up again, but it slipped out of his hands and almost off of the balcony. He couldn't control the line. Perry and Abner ended up trying to help him. The reeled the line in and they reeled in the car that Phineas, Ferb, and the others built.
"A car. Really? Curse you Perry the Platypus and Abner the Pig."
"See Mom… and it's not there." Candace mumbled.
"See? It's not there."
"But, Mom. It was there."
"The final score is 3-2." Gerald announced.
"Oh there you are Perry." Phineas smiled.
"Hey Abner." Arnold smiled.