Princess Bubblegum stood at her desk, hand poised over a row of jars. She hesitated for a moment, studying the labels on each one before picking up the one she was looking for. She scooped out a spoonful of the glowing blue powder and stirred it into the beaker she was working with. It fizzed and bubbled, sending up twists of blue vapour that smelt faintly of ozone.

Suddenly her vision was obscured and a voice whispered in her ear, "Guess who!" The steel spatula slipped from her grasp and hit the desk with a clatter.

"Marceline," the Princess cried in surprise, her hands going up to her eyes. She felt the rough fabric of the gloves against her palms as she pulled the Vampire Queen's hands from her eyes, "What are you doing here?"

"I was just passing," replied Marceline, picking up an apple that was sitting on the desk. She bit into it and drained it of all its colour before tossing the now grey apple into the bin.

"Hey, that was my morning snack," protested Princess Bubblegum, taking off her glasses and glaring at the vampire. To her annoyance Marceline began to laugh. "It's a little late for morning snacks, Bonnie," she explained, pointing to the clock. The hands read five past six. Princess Bubblegum's stomach rumbled in response to the lost hours.

"What were you working on anyway?" asked Marceline, floating upside down behind Princess Bubblegum, her arms behind her head.

"Just a little something," she replied evasively, setting the beaker on a Bunsen burner. She sat down on the stool, picking up a pencil and began making some notes.

"It must be one hell of a little something to keep you locked away for days on end," remarked Marceline. The Princess listened half-heartedly. She knew she hadn't been out of her castle for days but she had a good reason. She stopped, her pencil poised over the paper. The vampire's words had interrupted her chain of thought. She chewed at her pencil, trying to regather her thoughts. "None of us have seen you for ages. So what's the big deal?" continued Marceline, unfazed by the Princess' seemingly lack of interest.

"I'm just working on something rather special, something that will help...I hope," she said thoughtfully. Marceline waited but she didn't elaborate further and resumed chewing her pencil. She growled at the Princess' lack of proper explanation. PB looked around when she heard a sound like a gust of wind.

"Marce-," she began, thinking the vampire was taking out her annoyance on some object in the room, but the room was empty. She sighed, turning back to her work. She didn't notice the small bat hanging from one of the wooden beams that held up the high ceiling. Its beady blue eyes were fixed intently on the bubblegum princess. It dropped from the beam and opened its raggedy wings, gliding down until it was hovering near the princess' head. It scanned the writing on the page quickly before PB spun around. She hurriedly covered her notes with her hands, pouting at the bat that was rapidly shifting back to humanoid form.

"A potion to make vampires invulnerable to sunlight?" said Marceline incredulously, "Why?"

"It's not a potion. It's a chemical solution and I thought my motives were obvious," PB replied stiffly, "I wanted us to be able to spend more time together. Me, you, Finn, Jake and the rest."

"Are you sure that's a good idea?" asked Marceline, pointing to the beaker.

"Why wouldn't it be?" replied Princess Bubblegum, looking a little puzzled by her friend's reaction.

"I don't know," said Marceline, "I just...I've got a bad feeling, ok?"

"Marceline, it's all perfectly safe," reasoned Princess Bubblegum, "I haven't said a word to anyone about this experiment. Not even Peppermint Butler knows."

"Look, just...keep your wits about you," cautioned Marceline.

Beady red eyes regarded them from a dingy corner of the lab. A forked tongue flicked out, tasting the air and ears swivelled in their direction.

"Of course I will," retorted PB, "You shouldn't have been looking either anyway. It was supposed to be surprise."

"Don't get shirty with me, Bonnibel," snapped Marceline, "I'm just concerned for your safety."

"Alright, sorry Mar-Mar," replied Bonnibel, softer this time, "And I promise I'll be careful."

"Good, because it wasn't that long ago when we last had to save your bubble butt," teased Marceline, poking the back of PB's head. She cackled with laughter at the dense dark pink patches that appeared on her cheeks at these words. She looked out the window at the darkening sky.

"Well, I'd better go," she said, "I promised the boys I'd take them down to the Forest to run with the wolves." She was, of course, talking about Finn and Jake whom she was teaching about the night creatures. She described it as adding another string to their bow even though Finn was quick to point out he only fought using a sword.

"See you tomorrow, Bonnie," she said, swooping across the room to give PB a quick hug before darting out the window before she could so much as react.

Princess Bubblegum went over to the window and looked out at the rapidly fading speck that was Marceline. Something fluttered past her head. She turned to look but it was gone.

She returned to her desk and sat down, picking up the pencil. She sucked thoughtfully at the tip but for some reason she couldn't gather her thoughts together. The Vampire Queen's warnings must have unsettled her more than she had first thought. She put down the pencil and walked towards the door, pulling off her lab coat as she did so. She hung it on a peg by the door and turned off the light before exiting the room, locking the door behind her.

She made her way down the long winding corridors of her palace until she reached her bedroom. She changed into her pyjamas before slipping beneath the covers with a grateful sigh. 'The experiment can wait until morning,' she thought to herself as she drifted off to sleep.

The following evening saw her still working stubbornly on the solution. She had begun to make a little headway from what she could tell but she couldn't think of a way to test it. It would be far too risky to test it on Marceline. But then again she didn't know any other vampires and it was Marceline the solution was intended for.

"Hey Princess, you still working on your experiments?" came a voice behind her.

"Marceline, don't you ever knock?" replied PB in exasperation, "But I'm not sorry to see you though I hate to admit it."

"Is that so," grinned Marceline with mock affability, "And why's that?"

"Well, I think I'm making some headway here," said PB, gesturing to the notes on her desk, "But I need some way to test that theory."

"Whoa there, Bonnie," Marceline cut in, "You are not testing your potions on me."

"Well, I was hardly going to do it directly, was I?" replied PB, folding her arms, "I just need a sample of your DNA. A swab from your mouth would do." Marceline considered this for a moment.

"Alright, what do you want me to do?" she asked at length.

"Great," replied PB, clapping her hands, "Just sit there," she continued, gesturing to a chair. She opened a cupboard and removed a test tube and a cotton bud. Marceline hovered just above the chair and watched as the princess approached her, carrying the instruments.

"Open wide," she instructed. Marceline did as she was told and opened her mouth, displaying a set of sharp teeth.

"Hareful ou on't hick ourself," she warned as the princess made to probe inside her mouth with the cotton swab.

"I'll be careful," replied PB. Something slithery and wet flicked against her wrist. "Marceline, what are you doing?" She withdrew the swab from Marceline's mouth and put it in the test tube.

"What? I like bubblegum," Marceline replied mischievously. Princess Bubblegum's cheeks flushed a deep crimson. "Marceline, that's so distasteful," she cried. Marceline sniggered. The princess cleared her throat. "Anyway, I think I have enough DNA now," she continued, "I'll put the sample in my thermocycler and heat it to 98°C for 25 seconds to denature the DNA, and then I'll lower the temperature to 65°C for-."

"Bonnie, this is all Greek to me," interjected Marceline, leaning back in midair and crossing her legs, putting her arms behind her head.

"Greek? What's Greek?" asked Princess Bubblegum.

"It was a place before the Great Mushroom War," replied Marceline. She often forgot how little PB knew about before a huge chunk had been blown out of Earth in a catastrophic explosion, "The saying means I don't understand."

"Oh," she exclaimed, "I see. Anyway, basically I'll be able to make more of your DNA, enough to test my solution on."

"You're sure you know what you're doing?" asked Marceline, "I mean, keeping it under wraps and stuff?"

"Absolutely, Marceline," replied Princess Bubblegum, "I'm taking the greatest care. No one goes in or out of my lab without my say so, except for you of course. I can't exactly predict your sporadic visits at the best of times."

Satisfied with her answer Marceline smiled. "Why don't you take a break for a bit though?" she asked, "We could go back to my place and watch a movie." Princess Bubblegum looked at the half full beaker of grey liquid that was bubbling gently on the desk.

"Come on, you've been working solidly on this forever," coaxed Marceline, "A break would do you the world of good." Princess Bubblegum smiled.

"Maybe you're right," she conceded, taking off her lab coat and placing it on the peg.

"Is that a yes then?" grinned Marceline, holding her hands out to her. Princess Bubblegum nodded. The next second she gave a startled shriek as she was scooped up in Marceline's arms and flown out of the open window. She grasped tightly at Marceline's shirt, giving a frightened squeak when she saw how far below them the ground was. They sped along, the wind whipping back their hair and whistling in their ears. Marceline chuckled at the Princess' obvious distress.

"Relax, Bonnie," she laughed, "I'm not going to drop you." Princess Bubblegum buried her face in the Vampire Queen's shoulder in response. Her stomach did a somersault as they dove down lower. Marceline held her tighter, trying to reassure her that they were safe.

The Princess didn't open her eyes until she felt solid ground beneath them once more. Marceline put her down and she followed her into the cave where she had made her home. The house looked like any other house and the only thing unusual about it was its location. It had pink wooden walls and a brown tiled roof. A white picket fence surrounded the garden and here and there, beige coloured toadstools grew in the low lighting.

Marceline opened the door and led the way in. She lit a few candles that stood on either side of the sofa. "What do you want to watch?" asked Marceline, pulling out a drawer full of old tapes. Many of the cases were old and faded but the writing on most could still be discerned. PB knelt next to Marceline and cast her eye over the rows of video tapes. She picked one up and blew the dust off it. She coughed as some dust caught in her throat. "Geez, Marcy, when was the last time you watched this one?" she asked. Marceline took the tape off her and studied the cover.

"Hmm...I don't think I've ever watched this one," she replied, "I don't even know what it's about. Do you want to find out?" PB shrugged her shoulders.

"Alright," she said, curious about what the old tape contained. Marceline put it in the old VCR and pressed the play button. She settled down on the ground, hovering a couple of inches above the carpet. PB sat next to her, watching the screen as the film started. It showed a girl, presumably a human, moving to a new town and finding herself in a new school with some very strange company.

About a quarter of the way through the film Marceline made a noise of disgust. "Is that seriously how vampires were represented back then?" she scoffed.

"Those are...vampires?" said Princess Bubblegum in disbelief.

"Not true vampires," replied Marceline, "For one thing we don't sparkle and my eyes are still red. It has nothing to do with what I eat. That's just the way I am." Princess Bubblegum looked up into Marceline's eyes and saw that she was right. Her eyes were a deep crimson and glittered like rubies in the dancing candlelight.

A while later Marceline switched off the TV. "Sorry Bonnibel," she said, "I just can't stand another moment."

"That's alright," replied Princess Bubblegum. She leaned back, resting her back against Marceline's hip. She yawned.

"You getting tired?" asked Marceline. Princess Bubblegum shook her head before yawning again. Marceline chuckled again. She knew before long the bubblegum girl would be fast asleep.

As she predicted, barely fifteen minutes later, PB was curled up against her, breathing softly and evenly, one hand curled in Marceline's shirt. Marceline grinned, picking up the smaller monarch and gliding with her up the ladder to her room. She set her down on the bed and pulled off her boots. She pulled the sheets up around her. "Goodnight, Bonnie," she murmured, kneeling down and placing a light kiss on Princess Bubblegum's pink brow. Marceline yawned and stretched before gliding over to her closet to get a pair of pyjamas. 'Those vampires on the film might not need sleep, but I do,' she thought to herself as she shimmied out of her jeans. She put on her pyjamas before crossing the room to where Bonnibel was sleeping. She floated above the mattress, resting her head on her hands as she drifted off to sleep.

* * *

Marceline opened her eyes sleepily. The first thing she noticed was that she was lying on the mattress which was unusual for her. The second thing she noticed was the reason for this. A pink arm was wrapped around her middle and she felt soft breathing against the nape of her neck. She rolled onto her back and Princess Bubblegum snuggled closer, her head resting in the crook of Marceline's neck. The scent of her hair filled her nose. It smelt of...bubblegum unsurprisingly. She smiled to herself, thinking how gentle the Princess looked. Not like her sometimes hot-headed self during the day.

Princess Bubblegum opened one emerald eye and smiled. She yawned. "Morning Mar-Mar," she murmured sleepily. Marceline felt mildly surprised by the Princess' lack of embarrassment. She didn't have to wait long. Princess Bubblegum made to move her arms to stretch and hesitated when she discovered one arm wrapped around Marceline's waist. She sat up quickly, withdrawing her arm.

"Sorry Marcy," she apologised quickly, blushing furiously. Marceline was blushing slightly too, which surprised the pink monarch as she didn't know the Vampire Queen still had the ability to blush. "That's alright, Bonnie," replied Marceline, 'I wasn't exactly complaining,' she added in her thoughts.

"I guess I'd better be getting home," said Princess Bubblegum as she sat on the edge of the bed to pull her boots on, "Thanks for letting me stay, Marcy."

"Anytime," smiled Marceline.