Danville was a city that thrived on weirdness. It had seen portals to other dimensions, battles between platypuses and evil scientists, and at least three spontaneous musical numbers this week alone.

In the Flynn-Fletcher backyard, the weirdness continued.

Phineas stood proudly atop a wooden platform, arms spread like a ringmaster. "Okay, Ferb! Squirrel World is almost operational!"

Below him, squirrels zipped through tiny loop-de-loops, hopped onto trampolines made of acorns, and queued up for mini churros.

Ferb adjusted the gears of a hamster-sized Ferris wheel and gave a thumbs-up. A tiny bell dinged as a rodent rollercoaster car launched into a corkscrew.

"Ferb," Phineas said, eyes wide with awe, "this may be our most adorable engineering feat yet."

Upstairs, Candace Flynn stared out her window with the thousand-yard-stare of someone who's been gaslit by reality one too many times.

"They're building a squirrel amusement park," she whispered, watching a squirrel in sunglasses get its face painted by a robot arm. "This is not normal. This is not legal. This is... THIS IS THE BUST!"

She spun around, grabbing her phone and speed-dialing her mom.

"Hi, honey!" Linda Flynn-Fletcher answered cheerfully.

"MOM! You have to come home right now. Phineas and Ferb turned the backyard into a woodland rodent Las Vegas! There's a chipmunk DJ and a bungee-jumping booth!"

"Sounds creative! I'm so glad they're using their imaginations."

"No! No no no no—this is not imagination. This is structural engineering!"

Candace slammed her phone shut and groaned. "Every time. Every. Single. Time."

She paced across her room, muttering to herself. "They're too fast. Too sneaky. Too... prepared. I need someone who can get close. Someone they trust."

Her eyes narrowed.

"Isabella."

Across the street, Isabella Garcia-Shapiro was enjoying a calm morning with the Fireside Girls. She was halfway through ironing a sash of merit badges when her phone buzzed.

She checked the caller ID and raised an eyebrow. "Huh. Candace?"

She answered. "Hey Candace, what's up?"

"Emergency," Candace replied without hesitation. "I need a mole. Someone who can get inside my brothers' circle. Someone... who has a special connection to a certain triangle-headed boy."

Isabella choked on her lemonade. "You mean Phineas?"

"Yes. You're already emotionally compromised. Use it."

"Wow," Isabella said. "You have zero chill."

"Look, you want him to notice you, right? Here's your chance to impress him. All I need you to do is gather intel, record proof, and report everything back to me."

Isabella blinked. "So... you want me to spy on my crush... to help bust your brothers... and potentially destroy our friendship...?"

"Exactly!" Candace chirped.

There was a long pause.

"Fine," Isabella said with a sigh. "But only because the Fireside Girls don't have another cookie fundraiser until Thursday."

Candace and Isabella crouched in the bushes outside the Flynn-Fletcher backyard. Isabella wore a baseball cap and sunglasses. Candace held a clipboard, a walkie-talkie, and a complex-looking chart labeled "Probability of BUST vs. Probability of Insanity."

"Okay," Candace whispered. "Your mission: get close, gain their trust, get the dirt."

"I already have their trust," Isabella said, folding her arms.

"Good. Now weaponize it."

Before Isabella could argue further, a squirrel holding a tiny cane strutted onstage and began performing a full musical number.

Before Isabella could argue further, a squirrel holding a tiny cane strutted onstage and began performing a full musical number.

"...Is that a squirrel Broadway show?" Isabella asked.

Candace growled. "That is the evidence! Go!"

Isabella sighed, straightened her ponytail, and walked into the yard.

Phineas spotted her instantly. "Hey Isabella! Perfect timing! You wanna help choreograph the chipmunk chorus line?"

Isabella smiled despite herself. "Do I ever!"

She paused, then leaned into her earpiece. "Agent Izzy reporting in. Target is distracted by rodents with jazz hands. Proceeding with mission... reluctantly."

At Doofenshmirtz Evil Inc., Candace and Doof stood before a giant machine labeled "Slow-Mo-Bust-Inator 3000."

"Let me get this straight," Doof said. "You want me to fire a beam that slows time just long enough for your mom to catch your brothers red-handed...?"

"Exactly," Candace said. "We catch the chaos in motion. There's no way she can deny it this time."

Doof clapped. "Genius! Finally someone who appreciates my science! Perry the Platypus never lets me explain my inventions…"

They shook hands.

After another failed bust (the entire squirrel production vanished just before Linda looked), Candace stared at the remains of her latest plan: a glitter bomb trap that now just covered her in sparkles.

"I can't believe you didn't say anything!" she yelled at Isabella.

"You told me to spy, not sabotage," Isabella said, hands on her hips. "Besides, I like seeing Phineas happy."

"Well I like justice!" Candace snapped, storming off.

That night, Candace sat at her desk surrounded by scraps of plans, busted devices, and photos of inventions that should have busted her brothers ten times over.

"I need help," she muttered. "Someone who gets failure."

Her eyes landed on a newspaper clipping:

"Dr. Heinz Doofenshmirtz Paroled Again—Still Weird."

She picked up her phone.

"Let's bust some boys."

Phineas and Ferb unveiled their newest creation: a zero-gravity aquarium. Jellyfish floated in mid-air like balloons, waltzing to classical music.

"Hey Isabella!" Phineas called. "Want to help us teach them the tango?"

Isabella hesitated. Her spy mic buzzed in her ear.

"Agent Izzy," Candace whispered. "Get ready. Doof's firing the beam in thirty seconds."

But when Isabella looked at Phineas, smiling that brilliant, innocent smile, she turned her mic off.

"I'm done spying," she whispered. "Sorry, Candace."

Meanwhile, Doofenshmirtz aimed the beam.

"Three... two... one—PERRY THE PLATYPUS?!"

A fedora flew through the air. Perry tackled Doof, knocking the beam off-target.

The laser veered wildly—and hit Candace.

Time slowed.

Candace gasped as reality melted into syrupy slo-mo. Phineas danced in the air, Ferb poured glitter into a floating aquarium bubble, and Linda approached with a grocery bag, one frame at a time.

This is it, Candace thought. I've got this!

She bolted across the lawn, each footstep crunching in drawn-out slow motion. "Moooooommmmmm!"

But just as she reached Linda—

Time snapped back.

"Hi, sweetie!" her mom said cheerfully.

Candace whipped around—the aquarium, the jellyfish, even the disco bubble machine—gone.

"ISABELLA!" Candace shrieked.

Isabella twirled in a jellyfish costume. "Phineas let me keep it!"

Candace faceplanted onto the lawn.

That night, Candace sat in her room with a notebook titled "Plan C: The Chaos Gambit." She drew a big red circle around one name:

Buford Van Stomm.

"Time to fight chaos... with chaos."

Meanwhile, Isabella returned her mic to her drawer, placed a sticker over it that said "Retired", and smiled.

And somewhere across town, Doof stared at his busted Inator and muttered, "Next time, I'm adding jellyfish-proof wiring."