In the backyard of the house across Isabella's, two boys and a teal platypus are seen relaxing under the shade of a big tree, with the boys leaning on its trunk while the platypus lies between them.

The red-haired one with the triangle head asked: "Hey, Ferb, do you know what we can do today?"

The green-haired one with the long head, named Ferb, simply shrugged.

"What about you, Perry", the triangle-head boy asked the platypus. "You got any ideas?"

Perry simply chattered in response. Despite it being a simple creature that doesn't do much, the boy can tell that his pet platypus couldn't think of anything either.

After a bit of silence, the boy sighed. "Some days, you know exactly what to do on a day, yet other times you can't think of anything. I wonder why."

Ferb pointed at the sun.

"If it is because of the temperature", the other boy asked. "That's possible, but I don't want to test it. I like the sun's current heat, I don't want to plunge the world into an ice age just to get any new ideas."

Then the boy noticed something about the heat. "Although, it is kinda hot", the boy realized. "I'd like to go for a swim... but we already made a beach in the backyard."

Ferb pointed to the direction of the pink-purple house across the street where Isabella lived. The red-haired boy knew what he meant.

"That's it, Isabella has a pool in her backyard", the boy exclaimed. "Come on, Ferb, let's go ask her if we can dip in."

The two boys stood up and approached the wooden backyard gate. As they opened it, however, they were instantly met with Isabella... and eleven other kids the two boys never met before.

"Well, this is kinda weird", the red-haired boy said. "I should've figured you'd come here yourself."

"Oh, um, yeah", Isabella responded. "Anyways, whatcha doin', Phineas?"

"Well, we just wanted to come visit you and ask if we could take a dip in your pool", the boy, whose name was Phineas, answered.

"Oh, that's kinda why we're here", Isabella said. "Mom is maintaining the pool for the entire day, so we can't use it. And my temporary neighbors really want to take a swim in an actual pool, so I actually want to ask you if you can make us a swimming pool."

"Oh, that would be no problem", Phineas said. "But who are your new guests, anyway?"

The boy with the white hair approached Phineas. "Hi, my name's Lincoln-"

Lincoln was being pushed away by his older sister. "Beat it, squirt", she said. "Have you literally forgotten what I said a while ago? I do the introducing here."

"But Lori, you already introduced us earlier today", Lincoln said.

"Because I'm the oldest of us all", Lori stated. "And the same rule literally applies here too."

Lincoln groaned. "Fine", he agreed reluctantly.

Lori introduced herself, Leni, Luna, Luan, Lynn, Lincoln, Lucy, Lana, Lola, Lisa and Lily to Phineas and Ferb. Lincoln then approached the two boys and asked: "So, what's your name?"

"I'm Phineas", the red-haired boy said. "And this is my stepbrother Ferb. He doesn't say much, but he is a man of action."

Lana then approached Perry. "Ohh, what's this adorable creature", she said.

"'Adorable', she says", her twin sister Lola exclaimed. "I think you mean 'disgusting'!"

"I don't care what you think", Lana argued. "I like its duck bill and beaver tail." Lana asked Phineas again: "So who's this?"

"That's our pet platypus, Perry", Phineas said. "I'm glad someone likes it as much as we do."

Lola scoffed with disgust.

"Aren't the ornithorhynchus brown-colored with black appendages", Lisa asked, noting Perry's unusual coloration.

Phineas and Ferb looked at each other, before the former responded: "I guess. But ours isn't."

"We also have pets", Lincoln said. "This is our dog Charles, our cat Cliff, our canary Walt, and our hamster Geo."

"So", Lori said, "is it true you can build big things like a swimming pool? Aren't you a little... squirty for that?"

"Yes, yes we are", Phineas said. "And we'd love to make a big swimming pool. You can help us if you want."

"But can you do it", Lori asked.

"Of course we can, even when it's just Ferb and I alone", Phineas said.

As Phineas answered, their house's backyard door opened, revealing a long-necked teenager about Luna's age, but with a temperament more similar to Lori. She told: "Can you guys keep it quiet? I'm trying to watch TV!"

Phineas glanced at the girl before introducing the Louds to her: "Oh, that's our sister, Candace."

Candace then noticed the crowd in the backyard. "Phineas, who are these people? Are they part of another bustable plan of yours?"

"Oh, these are Isabella's temporary neighbors, the Loud siblings", Phineas told her. "We're gonna make a swimming pool for them."

"Sounds very bustable to me", Candace said. "You're going to be in so much trouble when Mom gets home!"

"Okay then", Phineas said obliviousy.

"Hey, I've an idea", Lori said. "While you guys work on the pool, I think it's okay to hang out with this Candace over here. Building pools is literally not for me and doing nothing is pretty boring."

"Sounds good", Phineas said. "Anyone else want to hang out with Candace?"

"Me", Leni said excitedly. "She's like my age group!"

"Eh, I'd rather rock my tunes out here with you guys", Luna said.

The other Louds also preferred to be with Phineas and Ferb.

"Hey, I didn't agree to hang out with these two", Candace complained.

"Oh come one, it'll be fun", Phineas said. "I bet you have a bunch of things in common. And even if you don't like them in the end, they'll be enjoying the pool when it's done."

"Candace couldn't think of an argument, so she reluctantly agreed: "Alright then. Come on, Loni and Leri."

"Those are literally not our names", Lori said.

"Yeah, and who's Larry anyway", Leni asked.

As Candace went inside with Lori and Leni, Phineas said: "Alright, i don't know what else has to be said, so let's begin! Ferb, can you pick up a few swimming pool blueprints at Blueprint Heaven, while we brainstorm for cool ideas?"

Ferb obliged and went off.

"Can I see Perry again", Lana asked.

"Oh sure", Phineas said. He looked around, but could find him. "Hey, where's Perry?"