Hey, Arthur, I Know What We're Gonna Do Today! by Emachinescat

A Merlin and Phineas and Ferb Crossover Fan-Fiction

SUMMARY: In which Merlin and friends get hit with a "young-inator," the boys turn their backyard into Camelot, Morgana smirks, Merlin's secret is revealed, and a disheartened Gwaine discovers that ginger ale and root beer can't get you drunk. Chaos and fun ensue.

A/N: I know, another story! But don't worry, this won't interfere with any of my other ones!

To all my Merlin readers: I don't know if you've ever seen or even heard of this show, but Phineas and Ferb has got to be the greatest cartoon ever! (In my humble opinion). This shall be purely crack!fic material, considering, well, that it's Merlin crossed with a cartoon… but it should be hilarious, hopefully, even if you haven't seen the show before. :) Inspired by my little sister, who is currently writing her own amazing crossover. It takes place right after S3 of Merlin and anywhere in P&F. It'll probably be 5-10 chapters. Finished fairly quickly, side-fic. Was going to be a one-shot but wanted to test out the waters and see if you guys are interested in me continuing. Should be good fun! XD

A few quick notes about P&F: (if you don't want to read or have watched it, you can go ahead and skip to the story. :) (1) Phineas and Ferb are like super-geniuses and can build/make/create ANYTHING even if it defies the laws of gravity but are totally modest about it, they just do it for fun. (2) Their sister Candace is a bit nuts and is obsessed with 2 things – "busting" her brothers and her boyfriend, Jeremy Johnson. (3) Every episode, Phineas and Ferb build something amazing, their sister tries to get them in trouble, and it disappears before their parents can see it. (4) Their pet platypus is a secret agent whose arch-foe is a goofy, not-so-sinister villain named Doofenshmirtz. (5) A running joke in the show are the words "Yes, yes it is" or "Yes, yes I am," etc. (6) There are lots of running jokes in the show that I'll try to include here, but they're small and not all that important so if you don't know or don't catch them, it's all good. :D That's it… I think. XD Sorry for the long A/N. :)

Please review!

Hey, Arthur, I Know What We're Gonna Do Today!

Chapter One: Oops… Wrong Spell

Arthur and Merlin were running. Again. They ran a lot, and not because they needed the exercise or because they liked blisters on their feet and calluses between their toes, but because they were always getting into some form of trouble. They had been chased by just about everything – magical creatures, bandits, soldiers, wild animals, thieves, sorcerers, and who knows what else. They had even chased each other around but usually in that case they weren't running for their lives – unless Arthur was chasing Merlin because he'd called him a prat again. Then Merlin was more than likely running for his life.

This time, however, it was not just the two of them running from the immortal army (really, you would think that after last time Morgana would have grown tired of undead men after her last plot, although this time Merlin hadn't had time to get the sword from the stone to kill the monsters, so he and his friends were at a disadvantage at the moment). Uther was cowering somewhere in his castle and Morgana had vowed to come back for him, knowing he wouldn't have the courage to run away. Gaius was with him, trying to make sure he didn't have another breakdown because of the stress.

The immortal army had charged for the real threats and those threats were currently dashing away from the undead folk that were hot on their heels – Merlin was in the lead, followed closely by Lancelot and Gwaine, who had Gwen sandwiched protectively between them. Arthur was in the rear, slashing away futilely with his sword (not the sword that could kill dead things, unfortunately) whenever he got the chance. Morgana was leading the undead army and was right on their heels.

Merlin knew that they were in a pickle, although how he knew what a pickle was when he lived in the middle ages, the world may never know. And it was a rather sizeable pickle indeed. He had to do something t get them away, out of the reach of the immortals, or they would all be doomed. He glanced behind him, seeing that no one was paying him any attention, not even Lancelot, who had his arm around Gwen's waist, keeping her steady, and a dreamy expression on his face. Gwaine was running and trying to dig out his last flask of ale at the same time, resulting in him almost pulling Gwen and Lancelot down with him. Arthur wasn't paying attention because he was too busy dodging Morgana's fireballs (which was probably a good thing considering that Lancelot was blushing as he held Gwen's hand to help her keep up.

Deciding that no one was going to notice him doing magic, Merlin thought for a second and then shot off the first spell he could think of – and unfortunately, he hadn't quite mastered this particular spell and may have possibly mis-said a word (or five). But what difference would a few syllables make? He asked himself dubiously.

He would soon find out.

Under his breath he muttered, "Cymryd pob un ohon sy'n byw oddi yma I danvillewch!" On second thought, maybe it was "ddiogelwch" not "danvillewch" but the damage had already been done. The spell had called for every living being nearby to be taken far away to safety – and although she was evil, Morgana was still living.

And of course, there was still the matter of Merlin getting the words mixed up…

As everything within a thirty foot radius was consumed by a blinding rainbow light, spraying a plethora of colors across the land and making everyone screw their eyes tight at the pulsing light, Merlin came to the realization that they would just have to wait and see where his spell took them…

He could only hope it would be somewhere they could get back from easily.

It was a normal day in Danville. The sun had been shining for thirty minutes and already ten-year-old Phineas Flynn and his green-haired stepbrother of the same age, Ferb Fletcher, had drawn up blueprints for their newest invention – a device that could make someone age or de-age with a push of a button. This was a little less intense than what they had done yesterday, their molecular separator, but it would still give them something to work on for an hour or two before they moved onto something else.

The whole Flynn-Fletcher family was sitting at the kitchen table eating breakfast. Linda, the mom, was attempting to chat with her husband about some new earrings she had spotted at a garage sale but Lawrence, whom she had met on a trip to Britain and fallen in love with, married, and then brought him back to the States, was wrapped up in a book. Candace, who was sixteen, had her bubblegum pink cell phone propped by her scrambled eggs, eyes darting continuously back and forth between food and phone. She kept muttering under her breath about when Jer-Bear was going to call, but her family mostly ignored her. They were used to her psychotic ramblings by now. Goodness knows that this was normal behavior for Candace! Their pet platypus, Perry, was munching away on Premium Platypus Chow right next to Ferb's seat.

Phineas, who had a shock of fiery red hair similar to his sister's (but spikier) looked up from his Cheerios and glanced over at his father. "Hey, Dad, watch'a reading?"

Lawrence looked up from his book, almost as if surprised to see he had a family sitting at the table with him, and smiled enthusiastically. "Sorry, all," he apologized. "This, Phineas, is a book about Arthurian legend."

Candace scoffed. "Oh, right, all that boring stuff Grandpa and Grandma like to go on about every time we go to visit them in England. King Artie and the knights of the brown table."

"Actually, it's King Arthur and the knights of the round table," their dad corrected but Candace had already tuned him out and withdrawn into her own little world, staring fixatedly at her cell phone with bug eyes almost as if she expected it to come to life and do a little jig. That had happened once, actually, when her brothers had made a machine that could turn any inanimate object into a disco-dancing pro. And that was one of the more normal things they'd done this summer. And people wondered why her stress level was so high for someone so young…

"He hasn't called me yet, and it's eight o'clock AM. I wonder if that's boyfriend code for playing hard to get or we need to talk…"

Linda glanced up from her own food and rolled her eyes in direction but didn't comment. She had learned that unless she wanted to turn gray ten times faster than she already was, she'd steer clear of Candace's "moments."

"Oh, cool!" Phineas exclaimed. "I remember Gramps telling us all about those stories. Arthur was the greatest king to ever live, wasn't he?"

"Many great leaders of today have modeled many of their political policies around King Arthur's rein," their father informed them. "Although sadly his story had a tragic ending…"

"What, someone steal his crown?" Candace snapped before tittering, "I think I should text him first, that shows I've got initiative, right? Or maybe it just says 'clingy'…"

"Actually, no," Linda jumped in on the conversation. Having a history buff for a husband meant she knew all of this stuff, too. "His best friend and his wife fell in love and he found out. It destroyed him."

Candace jumped out of her seat, eyes wide with panic. "Oh, NO!" she wailed dramatically. "That's it! Jeremy's got another girlfriend, that's why he hasn't texted!" She ran out of the room, sobbing. "Why? Why?"

Silence reigned for a few precious seconds and then Phineas glanced at his brother and grinned. "Well, the story may not have a happy ending, but all kinds of cool stuff happened in between, right? Like jousting tournaments, melees, damsels in distress, fights to the death, fire-breathing dragons, swords in stones—"

"And of course the greatest magician of all time – Merlin," Lawrence put in.

Phineas grinned. "Right. The guy with the beard that told King Arthur what to do." Phineas's eyes lit up. "Hey, Ferb. Why don't we put our other plans on hold? I know what we're gonna do today instead!"

Ferb (who didn't talk much) gave his stepbrother two thumbs up.

"Ferb, you've said it – we're going to make a medieval world in the backyard – we'll have jousting and a castle and a dragon…"

Linda smiled patronizingly at her sons. "Okay, boys, have fun." She chuckled fondly as the boys leapt from the table and dashed out the door. She grinned at her husband. "Kids," she smiled, "and their imaginations." She sighed and got up, grabbing Lawrence's barely touched dishes and headed to the sink. "Okay, I'm going to the flea market to see if they've still got those earrings and then Mrs. Garcia and I are going to get our hair and nails done. You'll watch the boys today?"

Lawrence's eyes darted up fractionally from his story about Sir Gawain and the Green Knight and he nodded. "Of course, dear."

Linda smirked. "And make sure Candace doesn't drive herself or anyone else crazy."

"Yes, dear."

She rolled her eyes. "And if a giant meatball falls from the sky, make sure you move the house out of the way."

"Right-O, darling."

She sighed, knowing her husband wasn't paying a lick of attention. "Right. Bye, dear."

As she strode out she heard Lawrence responding to her last comment distractedly. "Third drawer down next to the pickled eggs."

She really wasn't sure she wanted to know what he had thought she had said.

They all landed in a heap in the middle of a grassy field. Merlin, it seemed, still had terrible luck, even in wherever it was they had appeared, for he was at the very bottom of the pile. It would have been bad enough to be squashed by Arthur, the "fat prat" as Merlin liked to tease him when he was being particularly prattish, but adding Gwaine, Lancelot, Guinevere, and (he groaned) Morgana only made it worse. He could barely breathe.

One by one they clambered to their feet as best they could until finally the crushing weight was off Merlin, who didn't move. He didn't think he could move. He was pretty sure he had succeeded in becoming completely stuck to the earth's surface. Arthur rolled his eyes at his servant before bending over and peeling the boy off the grass before regarding him strangely. "You look thinner than ever, Merlin, have you been eating?"

Merlin gaped. "We've just somehow traveled by magic and you're asking me if I've been eating?"

Arthur shrugged. "Yes, yes I did."

Merlin blinked. "Okay." He glanced at Arthur. "You're looking a little thin, too."

Gwen gasped. "Why do I feel so… two dimensional?"

"How do we even know what 2-D is?" Lancelot wondered, gazing around in wonder as strange, colorful beasts on black wheels roamed what appeared to be solid black rivers. Houses, but none like in Camelot, lined the black river with white lines down the middle.

"I wonder where the tavern is," Gwaine said a little wistfully.

"Where are we?" Arthur growled. "And how did we get here?" He glared at Morgana, who had been standing stock still, eyes roving about frantically, at their new surroundings. "Did you do this?" he snarled. "You brought us here!"

Morgana glared at him. "Why would I do that? I had an undead army about to demolish you. Why would I whisk you away to somewhere so… un-dangerous?"

Arthur scowled. "Who knows what goes on in your foul little mind, she-witch!"

Morgana rolled her eyes. "Cut the theatrics, please, Arthur. The point is, I didn't bring us here. I'm just as miffed and startled by this as you are."

"But if you didn't…" Gwaine wondered, still looking around for the tavern, "…then who did… and why?"

Merlin put his hands in his pockets and began to whistle nonchalantly and everyone stared at him. "Er… when in doubt, whistle a merry tune?" he suggested lamely, realizing his attempt at being "casual" had only brought more attention to himself. "One of Gaius's many ancient proverbs…?" Everyone else lost interest except for Lancelot, who eyed Merlin suspiciously. He was the only one here that knew Merlin had magic and so he had probably already figured out who and was trying to decipher the why.

"Maybe… whoever did this meant to take us somewhere safe but accidentally brought us… here?" he suggested. Lancelot sighed and rubbed his temples. Merlin blushed.

Gwen stood up straighter and grabbed both Lancelot and Arthur's hands under the guise of being terrified (although the most terrifying thing here was Morgana, and she was currently in shock and not up to doing much evil at the moment) and asked, "Where is here?"

"Danville," Arthur supplied instantly.

Gwaine turned from his 'tavern-hunt' and stared. "You know everything, don't you?" He turned to Merlin. "How is it that he knows everything?"

Merlin pointed behind Gwaine, trying not to breathe too much of his ale-and-pickled-egg-breath. "I think he looked at the sign."

Gwaine looked over. A large white sign read "WELCOME TO DANVILLE." Gwaine nodded. "Ah." He glanced around. "Well, while we're here, we may as well have some fun, eh?" He grinned. He nodded at a little building across the black river where some of the metal beasts (which held people inside of them, how strange!) were getting fed through a hole in their sides from a giant contraption that said "GAS HERE." A sign in the window of the shop said "Ginger Ale and Root Beer – Half Off." Of course, Gwaine only saw the beer and ale part and was instantly besotted.

"Drinks, anyone? It's on Arthur."

Arthur glared at the knight and Gwaine grinned. Feeling the beginnings of a headache coming on, Arthur nodded. "Right. Drinks." He fumed at his knight. "On me."

Gwaine just laughed.

After everyone but Lawrence had left the kitchen, Perry the Platypus was jerked out of a sleepy stupor when his platypus bed flipped over and propelled him down a secret tunnel hidden under the house, down a slide slicked with what smelled like fish oil, and out of a tube, landing with a thud in his red swivel chair in front of a giant screen. He sniffed his arm, blanched, and glared at the gray haired man, his superior, Major Monogram, on the the screen. Perry did not look amused.

Perry was actually a secret agent animal that worked undercover fighting crime. His code name was Agent P and he was the best of the best.

Monogram winced. "Sorry, Agent P, but Carl," he glared at the red-haired intern that had just strode into sight next to him, "forgot to go grocery shopping this morning and we ran out of butter. So we had to slick the slide with fish oil." Perry didn't look impressed.

Carl, a nasally, red-haired college student with thick glasses and freckles all over his face, whined, "I'm sorry, Major M., but you're the one who wanted me to wait in line for those Justin Bieber concert tickets all night…"

Perry raised his eyebrows. Monogram glared at Carl and snapped, "Those were for my… er… niece, Carl. I told you."

"You don't have a niece, sir," Carl informed his boss almost mournfully.


Carl slunk out of Perry's line of sight and the platypus made his annoyed little gurgle. Monogram turned back to the business at hand. "Er, right – Dr. Doofenshmirtz is up to something. We know this because… well, because, he's always up to something… unless it's his day off… which it isn't… so…" Perry looked at the ceiling in exasperation. "Right – I want you to go find Doofenshmirtz, find out what he's up to, and stop him."

Perry saluted and then jumped in his little platypus-sized hovercraft as it whizzed by. Right before he was out of earshot, though, he heard Monogram say, "You did get those concert tickets, didn't you, Carl? Because I will – uh, I mean, my, er, niece, will be very disappointed if I… I mean, she, doesn't get to go…"

Perry rolled his eyes and soared out of headquarters and toward the lair of his arch-nemesis, Dr. Heinz Doofenshmirtz, evil super-villain wannabe extraordinaire (or not so extraordinaire, to be completely accurate).

A/N: Please review and let me know what you thought… my first time writing for Phineas and Ferb and I'm hoping I got it fairly okay… XD PLEASE review, I need feedback, I'd like to know if you guys would be interested in a continuation. I can only assure you it will get even funnier and awesome from here! :) Review!

~Emachinescat ^..^