I'm not sure when exactly to consider this story happening, because since I started writing it they've had all kinds of developments on the show. So, it's basically happening around the current point in the season, but I didn't include mentions of Lady being pregnant and wrote the first part shortly after "Burning Low", so I still have things a bit tense between Finn, PB, and Flame Princess. Other than that, it should fit in fine where we are now.
The other thing I'll add is that I'm no Rebecca Sugar. I put a song in here for Marceline because it felt right in the situation, but I hope you'll be forgiving that I've never written music before. That said, enjoy the story!
"You sure about this, man?" Jake asked, trying to figure out which end of the tent pole he held was supposed to go in the ground. "New girlfriend and your ex-girlfriend hanging out? Sounds like trouble."
"PB's not really my ex, officially," Finn said, laying out firewood in the middle of a circle of logs. "And I want to do this. I'm tired of everyone being awkward and fighting. I just want things to be like they were, but with Flame Princess included. She's excited to meet everyone, Marcie's cool with everything, and Bubblegum said she'd come, so she must be okay with it now. You sure Lady can't make it?"
"Yeah, she doesn't like to fly at night."
"Sorry, bro."
"No one asked if Beemo wanted to bring someone," Beemo muttered, throwing pebbles at the stack of firewood.
"Are you still mooning after Software Princess?" Jake asked. "You need to accept that you're just not compatible."
Beemo harrumphed, crossed his arms, and glared at the woodpile.
The sun set further, darkening the clearing where they'd set up camp. Down the hillside, a trail of flame could be seen streaking toward them, extinguishing the area behind it after passing.
"Look! She's here!" Finn grinned, bouncing up and down.
"No hugs without protection!" Jake called as Finn ran over to meet her.
Finn and Flame Princess stopped a chaste distance apart, smiling shyly at each other.
"Am I late?" she asked.
"You're right on time." Finn gestured to the woodpile. "Would you do the honors, milady?"
She gathered a fireball in her hands and lobbed it at the pile. The wood exploded into flame, sending embers scattering across the clearing. Beemo fell backward off his log and Jake stretched to protect the tent from igniting. The inferno shortly settled down to a neat, contained campfire.
Finn surveyed the area, patting out a smoldering spot on his shoulder. "Nice. Your control's getting really good."
As he and Flame Princess chatted, Jake resumed trying to sort out the tent. He finally got it balanced awkwardly and stepped back, nodding in satisfaction. A sudden gust of wind blew the tent over.
"Hey!" Jake scowled, then looked up to see the Morrow perched at the side of the clearing, Princess Bubblegum dismounting. "Oh, hey, PB."
"Hello, Jake." Bubblegum took her sleeping bag and a cooler down from the giant hawk's back, then waved it off on its way. "I brought the food. Where shall I put it?"
"Over by the fire's good." Jake looked at the tangle of canvas and metal poles, then tossed them off to the side. "Finn, I'm done with the tent!"
"Cool!" Finn looked over and saw Bubblegum. He put on a smile that didn't quite look natural. "Good evening, Princess."
"It's good to see you, Finn, Flame Princess."
In the pause that followed, Jake looked back and forth between them. "Yeah, this is gonna be fun."
"Aw, you're right, Jake," Finn said guiltily. "I'm glad you came, PB."
"Me too," she agreed, trying to be less formal. "And it will be nice to finally meet you properly, Flame Princess."
"You too," Flame Princess said politely.
"Can we get the hot dogs going already?" Jake grumped, wandering over to the firepit.
"Don't worry," Finn said to Flame Princess. "In no time, everyone's gonna be relaxed and having a good time…" He trailed off as he saw her eyes go wide in terror. "What is it?!"
"Behind you!"
He spun around to see a dark shape looming in the shadows of the woods. Red eyes gleamed and white fangs curved in the firelight as it snarled and lunged toward him.
"Oh, hey, Marceline."
The monster froze its leap inches from him and slumped with an annoyed sigh, shrinking back down to her normal form. "Man, you are so much less fun these days."
"Fool me a hundred and fifty times, shame on you. Fool me a hundred and fifty-one times…" He noticed Flame Princess still hanging back behind him, watching Marceline nervously. "It's okay, F.P. This is Marceline. Marceline, Flame Princess. Oh, glob!" His eyes widened. "Marcie, is the firelight going to hurt you?"
"Nah, fire's different than sunlight." She looked past him and gave Flame Princess a grin. "Nice to finally meet the new girl I've heard so much about."
"Good things!" Finn interjected. "All good things!"
"I remember you," Flame Princess said, stepping a bit closer. "My father kicked you out of our kingdom a few years ago."
"Yeah, that guy had no sense of humor," Marceline snorted. "So, the genie finally escaped her lamp, huh?"
Now Flame Princess smiled. "Yes, Finn and Jake helped me get out and I'm staying in this kingdom now." Her fire flared as she clenched her fist. "I'm tired of my father controlling my life."
Marceline gave her an approving nod. "I get that. Well, come on," she continued, swinging her bass off her shoulder and floating toward the campfire, "let's get this cookout going! Hey, Bonni! You doing the cooking? I'm starved!"
Bubblegum looked up from preparing hot dogs and hamburgers for the fire. "I thought you preferred to bring your own food."
"What, you brought stuff for everyone except me? Not very princess-like."
Bubblegum held her petulant glare for a moment before rolling her eyes with a sigh and handing Marceline a cinnamon candy piece from the cooler.
"Aw, knew I could count on you."
Flame Princess watched her sit back in the air beside Bubblegum. "You don't drink blood?"
"Nah, just the color red, usually from fruit." She looked over at Bubblegum, who held a raw hamburger patty in one hand while distracted with something in the cooler. "Of course, every now and then…"
Silently, she floated closer to Bubblegum. The princess looked back in time to see the hamburger being drained of color. "Marceline!"
Marceline sat back, all affronted innocence. "What? It's gonna turn gray when you cook it anyway. And I left the juice in it."
Bubblegum grumbled and set the patty apart from the others, then went back to her preparations.
Finn laughed as Jake sniffed at the partly-drained patty. "Man, we should've done this way sooner. I've missed hanging out together." He picked up a stick and speared a hotdog on it. "FP, you want me to start one for you?"
"Oh, I can do it myself." She reached over and picked up one of the burgers. She placed her palms on either side of it and pressed. Steam rose between her fingers. When she opened her hands, a charbroiled burger sat inside.
"Trigonometric!" Finn bounced on the log, putting down his roasting stick. "Would you do one for me?"
"You can have this one." She moved to hand it to him, then realized he had no plate.
"Hang on, check this out!" Finn dug through his backpack and came up wearing a silver, crinkled glove. "Tinfoil gauntlet! Pretty sweet, huh?"
With his gloved hand, he took the burger from her and put it on a bun. "See? This way we can actually hold hands and stuff…" His face reddened and he stuttered, "Uh, you know, if you want to."
Flame Princess responded by smiling shyly and reaching out to take his hand. Both brightened as they shared their first time holding hands without any pain.
"It works!" Finn cheered. "It's like twenty layers thick. Go ahead, really give it some heat."
Flame Princess sent more heat to her hands, her fire taking on a white color. Bubblegum winced nervously and Marceline flinched a bit.
Finn tried to look stoic, but his arm started shaking and he bit his lip. "Okay," he said in a strangled voice, "maybe it needs more layers."
Flame Princess giggled and let go of his hand. Finn chuckled too, flexing his fingers to be sure they still worked. Bubblegum sighed and focused back on her burger, which Marceline couldn't help noticing with a grin was the pale patty.
Beemo sighed. "Software Princess used to let me exchange files with her mainframe."
Jake groaned. "None of us want to know about that, Beemo!"
And so talk turned more relaxed as everyone ate and chatted. Inevitably, once all were full and spirits high, talk turned to music.
"You have got to hear Marceline play," Finn told Flame Princess. "It's bizonkers! If you're up for it, Marcie."
"Yeah, no problem." Marceline pulled her axe from behind the log and tested the tuning. "But all of you need to jam too. I don't feel like getting serious tonight. Y'all know way too much about me already."
"Sure thing," Finn agreed. "Jake, you brought your viola, right?"
"Is the Ice King desperate and lonely?" Jake stretched his arms over to get it out of Finn's backpack.
Bubblegum leaned down to where Beemo sat, playing a game against himself. "Are you ready?"
Beemo paused his game to eye her warily.
"I promise, no algorithms this time. Just free-styling."
"Okay." He logged out of his game and let her pick him up and begin picking at his circuitboards.
As Finn warmed up his lips to beatbox, he looked over at Flame Princess. "Globbit, I forgot to ask if you had an instrument to play!"
"It's all right. I can make one." Flame Princess scooped up handfuls of the sand around the firepit. She melted each handful into glass and stretched them out to form hollow pipes of different lengths. As she ran her hand under each one, the hot air rushed through, making different haunting notes.
"Whoa…" Finn stared, mouth open.
"Okay, I am so bringing you to my next show," Marceline said. "Ghosts would go poltergeist over that! Here, see if you can follow this."
Marceline strummed out a tune and Flame Princess found a complementary rhythm. Jake joined in and Bubblegum devised a theme as Finn rolled out a beat. It didn't take long for the sound to blend into a layered, vibrant melody.
Eyes closed, Marceline started humming along, and her voice soon followed, low and smooth.
"Starlit skies
Under a bloodless moon arising
They gather in the firelight with shadows on all sides
Keep the darkness at bay 'cause that's where demons like to play
And never from the firelight will you stray
No matter what sweet temptations they lay"
Bubblegum frowned a bit at that line and looked up at her suspiciously. Sure enough, the vampire was lost in the music, probably barely aware she was singing. But Bubblegum was listening closely as her voice became stronger and more pointed.
"No, stay in the light, and never brave the night
You'll never know the thrill, but you'll never know the fright
And one day you may wonder if it was maybe worth the fight
And if the choice you made was really right
But you'll only hear the silence of the night…"
She broke off, like someone startled out of a dream, as the ground trembled beneath them, their instruments stuttering to a stop.
"I think something really likes our music!" Finn shouted over the rumbling.
"Or really hates it!" Jake yelled back.
The ground in the middle of their camp suddenly exploded upward, knocking them all backward. Through the spray of dirt and embers, a giant, white, serpent-like monster erupted into the clearing.
"What the crud?" Finn gasped.
"I don't know, man. I've never seen one of these before." Jake leapt back as a coil of the monster landed on the ground before him.
"Get the princesses!" Finn ordered. He turned to the serpent. "Hey! Nobody ruins my campouts!"
He drew his sword and the creature's head snapped in his direction. Finn saw then that the pale head had no eyes, just sockets with skin stretched over them. Still, it seemed to stare directly at him, tendrils around its snout twitching. It opened its mouth and a black tongue lashed out of it.
Finn braced to slice at the tongue, but was suddenly swept off his feet and into the air. The tongue passed right where he had been standing and hit a tree, which immediately withered and cracked.
Finn looked up to see Marceline in her bat form gripping him by the shoulders. She darted back and forth around the clearing, the snake following their every move.
"Cover your ears!" she shouted.
"What?"
"Just do it!"
As Finn wrapped his arms around his head, Marceline turned around to face the serpent head-on and released an ultrasonic screech. The creature recoiled with a hiss and turned its attention toward Jake and the princesses instead. Marceline shrieked again and this time the serpent dove back into the soil, burrowing away.
"Where'd it go?" Finn asked as Marceline set him down and shifted back to her normal shape.
"Away, for now," Bubblegum said. "We need to get back to my labs and figure out our next course of action before it surfaces again. Morrow, to me!"
The bird landed and they climbed aboard, Finn making Flame Princess a blanket of tinfoil to sit on. Marceline, though, hovered at the edge of the tunnel left by the monster, examining the now-dead grass of the clearing.
"Marceline, are you coming?" Bubblegum called. "It'll be faster for you to ride than fly."
"Huh?" Marceline looked up, still distracted. "Oh, yeah. I'm coming."
She joined them on the Morrow's back, but as it took off, she kept staring back at the tunnels in the campsite.