I couldn't get the idea out of my head, so I had to write it down! . I'm starting out by rewriting episodes with Marceline in it, but replacing them with Marshall and Fiona. But I'll branch out and do my own editions as I write more. The updates may be inconsistent, so I apologize. I hope you enjoy it. And please review and let me know what you think. Suggestions, comments, opinions, anything's appreciated :)

Chapter 1

Lightning flashed outside the tree house, accompanied by an earsplitting boom. Rain pelted the house relentlessly, the heavy pitter-patter echoing throughout the house. Fiona, brushed her blonde hair from her face as she sat listening to Cake's story. The only thing keeping her long hair from tumbling all over the bed was her white rabbit-eared hat.

"And as it waded through the carnage it had wrought, the vampire SMASHED THEIR SKULLS!" Cake squeezed the jelly donut in her paw, her claws digging into the dough. Red jelly oozed out from the pastry. "Just for the fun of it!"

Fiona gasped. "No way!" Dressed in a simple red fleece nightgown, she inched further into the sleeping bag. She pulled the fur blankets closer. "Stop it, Cake! You're just messing with me, aren't you?"

The white and orange cat smirked. "Yes way, it did!" She stood up and approached the bed. "And then the vampire hunched over its victims and breathed their vaporized blo-o-o-od mi-i-i-ist!" Cake waved her fingers spookily. "Oo-o-o-o-o-o~!"

"Ew, gross!" She gently shoved her away. "You're making this up, right? Is that stuff really true? Be honest!"

"Girl, it's true! Trust me, I heard it from a very reliable source." Cake grinned. "Have I ever lied to you?"

"Reliable?" She groaned, pulling the blankets closer. "Man…."

"And you know what? Some say the vampire used to haunt this very tree!"

"This tree?!"

"M-m-mhm!" Cake picked up the candle from the nightstand and started to climb down the ladder. She snickered. "Good ni-i-i-ight," she said in a spooky tone.

"Cake! You're full of it, Cake! I know it!"

Soon the candle's faint glow disappeared as Cake climbed downstairs. As Cake's soft footsteps faded, Fiona sunk down below the covers. She pulled them up over her shoulders. Occasionally a bolt of lightning would illuminate the bedroom, accompanied by a loud rumble of thunder. The droning sound of rain was constant. She glanced around the room nervously. Fiona didn't really believe Cake. She always liked to tell stories to try and scare her. But for some reason, the atmosphere just made the story that much more believable. She rolled over in her sleeping bag. All of the shadows seemed more menacing for some reason. It was probably just Cake's story messing with her head. Fionna sighed.

A light tapping sound startled her. Fiona gasped, her eyes snapping open. She sat bolt upright in bed. She scanned the room, but nothing seemed out of the ordinary. Then she heard it again. She fixed her eyes on the window. She could faintly make out the blurry outline of a tree branch outside. It was scraping against the window thanks to the strong wind outside. Then something outside moved. A shadow passed over the glass. The silhouette of person appeared in the lower corner of the window, tapping on the glass. Fiona squinted, trying to get a better look. A flash of lightning illuminated the room. She caught a glimpse of a pale face shrouded in black hair. Bright red eyes glowed. There was a hiss. And as quickly as she had seen it, it was gone.

Fiona screamed. "Cake! Cake!"

Cake's rushed footsteps scrambled up the ladder. The room was lit up with candlelight as she emerged at the top of the ladder. "What's goin' on, baby? What're you screamin' for?"

She leaped out of bed and rushed over to the cat. "I saw someone outside the window! It must be the vampire." Her heartbeat pounded in her ears. Fiona's blood was pumping and her mind was racing. Cake wasn't lying! There was a vampire! "And we're totally unprepared so—"

Cake burst out laughing. "Relax, girl! I made the whole thing up. I was just tryin' to scare you." She nudged her in the side and winked.

"Wait." She narrowed her eyes. "You said you heard it from a reliable source."

The cat snickered. "I made that up to. I was just tryin' to scare you, Fiona. And it worked! Take it easy, baby."

Suddenly the windows burst open. The candles blew out. Cake leaped back, all her fur standing on end. She hissed. Some of the rain blew in through the open window. She hid behind Fiona, the fur on her back bristling. Fiona hurried to the window. She leaned her head out and glanced around.

"There's nothing there…." Fiona pushed the windows shut and locked them. "It was just the wind, scaredy cat!"

Hands on her hips, Cake frowned. "You take that back! You know how much I hate that term! It's demeaning." She turned away in a huff. "Besides, I wasn't scared…" she muttered.

Fiona laughed. "You're such wimp."

A thump behind them made them both jump. Fiona snatched a flashlight from the nightstand. She flicked it on and pointed the beam toward the source of the sound. A large duffle bag lay on the floor, close to the ladder.

"Huh? How'd that get in here?" She started to approach it.

"Oh, girl, we got trouble!" Cake's tail bristled, doubling in size. "My tail is totally frizzing out!"

A dark chuckle echoed in the bedroom. Fiona pointed the flashlight up, searching for the source of the voice. The beam illuminated a pair of red converse sneakers before finding the rest of the body. A teenager in jeans and a red and black checkered shirt was floating near the ceiling. He had short black hair and pale skin. He chuckled again and hissed as the flashlight lit up his red glowing eyes.

Fiona screamed, stumbling back toward the bed. Cake shrieked, then hissed. Fiona tripped, falling back onto the bed. The boy floated down toward them. He slowly lowered himself between them and draped his arms around them.

"Hey, guys," he said calmly in a dark voice. "What's up? Never seen you two here before." He grinned, revealing his sharp fangs. "I'm Marshall Lee, the Vampire King."

Trying not to act scared, Fiona scooted away slowly. She was shaking as she stared at him. "A-are you gonna smash my skull and b-breath my blood mist?"

"Don't suck our blood!" Cake trembled.

Marshall laughed. "Calm down, scaredy cats, I'm not gonna do that." He snapped his fingers and the candles in the room burst to life.

"Hey! I take offense to that!" Cake frowned, hands on her hips.

"Yeah, whatever, kitty."

"So…" Fiona said hesitantly. "You don't suck blood?"

He smirked. "Sometimes I do. But it's not the blood I like, it's the color." A mischievous glint leaped into his eyes. Marshall gently took Fiona's hand and lifted it to his lips. With a soft hiss, he sunk his fangs into the sleeve of her nightgown. The red slowly drained away toward his mouth, leaving her in a gray gown.

Fiona jumped. She shoved him away, her cheeks slightly flushed. "What the heck're you doing?!"

Marshall chuckled. "You're funny. Never seen a girl like you before." He floated up, leaving Fiona and Cake, slightly shaken, sitting on the bed. He hovered in the air as he started toward the duffle bag. He yawned. "I'm beat. Been traveling all over Oo, and man, I've seen some stuff that would really make you say 'like what'."

"Like what?" Fiona sat up straighter.

"Let's see." He rummaged through his bag. "I found a school of goldfish beasts, and fooled around in the Fire Kingdom. I tell you, they throw some freaky nasty parties up in there."

"Wow! That sounds amazing!"

"Fiona," Cake whispered nervously.

"Oh yeah! Check these out." Marshall floated toward them and sat down between the two. He held out his hand, a couple of walnuts in his palm.

"Nuts?" Fiona arched an eyebrow. "What's so special about that?"

"Oh, these aren't just ordinary nuts." He smirked. "Get a load of this."

He squeezed the nuts until a sharp cracking sound came from his palm. When he opened his hand, little multi-colored animals were crawling around where the walnuts had been. They leaped off his hand and crawled all over Fiona. She giggled.

"That's so cool! You're not so bad, Marshall."

"Yeah…" Cake said nervously. "Thanks for not sucking our blood."

"You guys seem pretty cool too," he said. He yawned again and stretched. "But you know, I'm pretty tired, so you two should probably get going."

"Huh?" Fiona sat up straighter. "What are you talking about?"

He sighed and waved his hand toward the tree trunk that grew through the middle of the room. "Look." A picture nailed to the tree moved suddenly, revealing a faded M carved into the bark. "M for Marshall."

"O-o-oh no…." Cake scooted closer to Fiona. "What're we gonna do?" she whispered.

"Calm down."

"Yeah, I carved it in this tree years ago. Wa-a-ay before you girls started livin' here," Marshall said. He wrapped one arm around Fiona's shoulder and the other around Cake's. He lifted them off the bed and floated them over to the window. Rain was still pouring. Cake hissed, her fur bristling as she got wet. Marshall set them on the ground and floated back up to the bedroom window. "Seriously though, thanks for keeping the place warm for me. That was really cool of you."

Cake shrunk down and climbed under Fiona's white hat. She curled up, hiding from the rain.

"Later!" Marshall hollered as he closed the window.

"Hey, wait!" Fiona shouted. "You can't just kick us out of our house!"

"Come on, Fiona," Cake hissed. "Let's just get out of here!"

Fiona pounded on the door. "Get down here, dude! I'll kick your butt!"

"Fiona, wait!" She dug her claws into Fiona's hair, making the girl wince. "Girl, he's a vampire!"

Suddenly Fiona's pillow and backpack landed on the ground, along with Cake's dulcimer. "Hey!" Fiona glared up at the bedroom window. Marshall chuckled and closed the glass again. "I'm gonna kill him," she muttered.

"Girl, if half the stories I've heard and or made up are true, vampires will kill you," Cake said. "There's no doubt about it!"

They both glanced up at the window. Marshall was pressed up against the glass, watching them with an evil smirk on his face. His eyes glowed red as another bolt of lightning streaked across the sky. He chuckled and disappeared into the house.

"But what about our house?" Fiona persisted.

"A vampire took it!" Cake said angrily. "Don't worry, baby. We'll just go house hunting!"

"But I like our home…I dunno…."

"Girl, trust me! It'll be great."

Fiona sighed, scooping up the things Marshall had dropped. "Alright. I guess it's worth a shot. Let's go…."

V* V* V* V* V* V* V* V* V* V* V* V* V* V*

Marshal floated lazily across the room, but stayed close enough to the window so he could see out. Fiona was still down standing in the rain, arguing with her cat. Finally she picked up her stuff and trudged off in the direction of the Candy Kingdom. He hovered close to the window, watching her go.

"What a weird girl," he muttered.

Arms folded behind his head, he stared up at the ceiling. Now that she had left, the tree house was awfully quiet. Maybe he had been a little harsh with her. She was a girl after all. But what did he care? He was Marshall Lee—the Vampire King. He catered to no one. And it just so happened that he wanted to crash in his old house, so he had to get rid of the new tenants. He pulled his red axe-shaped base from his duffle bag. He strummed away, humming softly to himself. And as he played, the sun slowly rose over the horizon, casting warm rays in through the window. He hissed and darted into the shadows.

"Man, this bites." He sat down in the shadowy corner and strummed his bass. "If I had known it was gonna be this boring, I wouldn't have kicked them out right away."

They seemed like pretty cool girls. Suddenly an evil idea came to him. They had seemed pretty bummed that he kicked them out of their tree house. It might be fun to mess with them a little more. Snatching a wide-brimmed hat and jacket from his bag, he pulled them on. Using his vampire powers, he turned invisible and flew out the window after them. He chuckled to himself as he watched them go house hunting. Some of the places they tried were ridiculous. Places like under rocks, hollow trees, and Fiona even suggested a beehive at one point. But when they finally made it to an old cave near the ocean, their spirits seemed to lift. He floated lazily, unseen, near the mouth of the cave. He watched as the cleaned up the place and built a little house near the water. It was kind of disappointing how upbeat they were. Heck, they even threw a party.

This should be fun, Marshall thought. Let's see what they'll do when I crash their little party.

By now it was nighttime. He tossed off the hat and jacket and released his invisibility power. He threw open the door and strode inside. He danced to the music they had playing. Marshall snuck up behind Fiona.

"Nice party you got goin' on," he said.

Fiona jumped. "Marshall?! What are you doing here?"

"Just came to chill. I see you got yourself a pretty nice place."

What do you want?" she asked, annoyed.

"Fiona," Cake whispered nervously.

"Oh, I just wanted to show you something." He waved his hand, a small rock flying across the cave. The stone floor beneath where the rock had been had an M carved into it. "This cave belongs to me!"

"What?!" Fiona shouted. "You can't be serious! You can't take our home again!"

He chuckled. "Oh yes I can!"

"I'll kill you, you jerk!"

Cake grabbed her arm. "Fiona, honey, wait! Let's just find a new place."

"No way! He can't just take our house again!"

"Fiona, vampires will kill you! Besides, home is where your friends are, remember?"

Fiona sighed. "Fine…." She glared at Marshall. "Okay, Marshall. You can have this place, but only because Cake is my home. And she's way better than all your homes combined!"

He arched an eyebrow. "That so? Well, then." He swooped down and snatched Cake away. "How about I just take her then?"

"Cake!"

"Fiona! Help!" Cake was trembling.

"Maybe I'll just bite her…turn her into a zombie slave."

"Uh-uh! No thank you!" Cake squirmed in his grasp.

"Give her back!" Fiona shouted.

He smirked. "Make me."

Fiona charged at him. She swung at him, but he avoided her easily. He laughed as she tried to punch his lights out. She had spunk. He liked that. He smirked and tossed the cat down at her. Fiona caught Cake clumsily. She glared up at him.

"What gives, Marshall? What's with you?" she said.

"You know, you're alright. I like you. So I'll tell you what." He floated closer to her. "I'll let you keep your little tree house. Think of it as a present from me."

"What?" Fiona was taken aback. "For real?"

"Yeah." He snatched her chin and pulled her closer. "Just don't get too comfy, girl. Remember, I'm a vampire. So I'm not good." He sneered. "Don't forget it."

She slapped his hand away. "Yeah, whatever. But thanks anyway."

"Come on, Fiona! Let's get out of here!" Cake hissed.

"Yeah, go on. Scram!" Marshall laughed as they high tailed it out of the cave. She was definitely an interesting one. He'd been in desperate need of entertainment. Touring Oo had been fun and all, but he had been getting pretty bored—especially since he didn't have anyone to hang out with. But she seemed cool enough. He grinned at the thought of messing with them again. Things were starting to get interesting.

Chapter 2 coming soon!