Adventure Time © Pendleton Ward/Cartoon Network

Fallout © Bethesda/Interplay


Somewhere in the Land of Ooo, a very pale skinned woman with long, flowing hair as black as night
was floating a few feet above ground, humming to herself as she strummed an axe-shaped guitar.

"let's seeee...(strums a cord) Naw, that doesn't sound right." spoke the woman.

"Dang it, Marceline! You can do this. You're the AWESOME Vampire Queen, remember!?"

Marceline stopped, and continued to strum some random strings on her guitar.
Her ruby eyes then turned full red as she started to get frustrated.

Hissing like a serpent, she began strumming her guitar with such fury,
that it might've made even the hardest heavy metal player blush.

The quote/unquote 'Music' that she created then created a burst of energy,
which surrounded the Vampire/Demon half breed, swirling around her like a vortex.

"WHAT THE FROCK!?" exclaimed Marceline, as she was engulfed by the strange energy.

As the magical wind swirled around her, Marceline's massive mane of dark hair billowed upwards.

The dark forest was soon swallowed up, replaced with a pitch black darkness.
The clean air also changed, now giving a very musty scent that disoriented Marceline for a moment.

Once the wind faded, Marceline's nocturnal instincts kicked in as her eyes shined white,
and began to focus in the darkness that would've left anyone else blind.

The Vampiress soon realized that she wasn't outside in the woods anymore.
Instead, she was in some kind of dark, enclosed room of some kind.

"what the holy grob is going on here?" muttered Marceline, as she searched around the enclosed room.

Eventually, Marceline found what appeared to be a light switch and flipped it on.
a ceiling light flickered for a moment, before finally turning on. Banishing the darkness.

Marceline quickly found that she was in what looked like an office of some kind,
that had filing cabinets, a desk and a strangely shaped computer that was blinking a green light.

Still confused, Marceline decided that the best way to find out more
on what this strange place is, was to look at whatever was on the computer.

Sitting down, she tapped a random button. Instantly text in green appeared.


[Welcome to ROBCO Industries (TM) Termlink. Thank you for choosing Vault-Tec!]


Marceline raised an eyebrow. "Vault...Tec?"

The next thing Marceline looked at was the computer's internal clock...

...and her eyes nearly popped out of their sockets.


['October 23rd, 2287. 8:44PM']


"TWENTY-TWO EIGHTY-SEVEN!?" exclaimed Marceline, shocked.

"but...THAT'S IMPOSSIBLE! wait...is this thing Pre-War?"

Marceline took a moment to think. "if that's true, then...That date STILL shouldn't be right. The year should be 3077."

Marceline then widened her eyes as it suddenly dawned on her.

"holy grob, I'M 1000 YEARS IN THE PAST!" screamed Marceline.

"I think. This hunk of junk COULD still be outdated. But still...Frock!, how in the Nightosphere did this happen!?"

It was then that Marceline noticed some lights turning out on the other side of a door.
Curious, she wielded her axe guitar and carefully opened the door.

To her surprise, she found a chamber that was as big as a standard Gymnasium.
Walking out, the first thing that caught her eye was a massive, Gear-shaped door.

Said door looked very sturdy, and was sealed tight...like a Vault.

("OHH...so THAT is what 'Vault-Tec' means. DOY.") thought Marceline.

Marceline then froze, her mind drawn back to when she was a little girl over 1000 years ago.
Back then, she had been wandering the ruins of the old world, First with her mother, and then...Simon.

As such, Marceline knew instantly that this place must be some kind of Pre-War Fallout Shelter
(Sort of similar to her old home, 'The Clubhouse', only much, MUCH better put together.)

"looks like that's my way outta here." mused Marceline, as she flew over to the giant vault door.

Marceline then drew out her Axe Guitar, and whacked one of it's bladed sides against it.
Predictably, the weaponized instrument deflected from the thick metal with a loud clank.

Marceline struck it again (harder this time), and was recoiled for her troubles.

"yeah, this thing ain't budging." mused Marceline to herself.

Marceline then flew away from the massive vault door, floating as she took a moment to think.
She then spied a computer console not far from the door, and instantly flew over to it.

"Alright, this must be how I-wait, where's the controls?... WHERE'S THE DING-DANGED KEYBOARD!?"

Marceline looked, and found only a strange looking port.

"something important must go here..." grumbled. Marceline

"Shizz, I really wish Bonnie were here. This is more of *her* thing."

Marceline sighed sharply, realizing what she had to do.

"Guess it's "Adventure Time" for ME..." muttered the Vampire girl,
(immediately feeling awkward upon saying Finn & Jake's infamous catchphrase.)

Marceline floated over to the only other doors in the room,
which slid open like something from out of Science Fiction, revealing a long tunnel.

Marceline huffed and entered the tune-like tunnel, floating above the ground as she traveled down it at a steady pace.

"I suppose this place isn't TOO bad." spoke Marceline to herself.

"This would've made an awesome clubhouse back when I was a lil' Vamp!"


Marceline continued down the tunnel, until she reached some other sliding doors.

Curious, she opened one. Inside she found a large room that resembled a cafeteria with long tables lined up, and various chairs placed beside them.

Also inside, there was a kitchenette where food was no doubt prepared.

"Cool!, maybe there is something Red in here to snack on!"

Marceline quickly flew in, and checked the cabinets and fridge.
Unfortunately, they were all bare. with only empty cans and utensils to be found.

"of course it's empty...crud." grumbled Marceline, mildly annoyed.


((*SKREEE!*))


Marceline quickly turned, started by a sudden high pitched noise.

She then froze upon seeing a HUGE cockroach the side of Jake skittered towards her.

With her old survival instincts kicking in, she quickly drew out her axe guitar
and as the giant roach leapt towards her...she swung her axe, slicing the insect in half.

Breathing heavily, Marceline stared at the remains of the giant bug she killed.

"guess this place wasn't sealed as tightly as I thought." mused Marceline.


((*SKREE!*))


Marceline widened her eyes as three more giant roaches appeared.

"oh, frock me." groaned Marceline, more annoyed than scared (actually, she wasn't scared AT ALL.)

As the giant roaches attacked, Marceline acted quickly as usual.

With lightning fast reflexes, she threw a wooden stake at one Roach so hard
that it was not only impaled, and literally NAILED to the metal wall.

Marceline followed up with another swing of her axe guitar, slicing up the second roach.
The third and final one, she simply stomped real hard with her boot, CRUSHING it.

"EAT DAT, SUCKAHS!" exclaimed Marceline, feeling mighty proud of herself.

[Later.]

Marceline stepped through yet another sliding door, and found a medium sized room.
The room had a much rounder shape, with a desk at the center that was curved like a crescent moon.

However, as Marceline examined the room...she froze and gasped upon seeing a morbid sight.

At the far side of the room was a simple cot...and laying upon it was a clothed skeleton.
Said skeleton was dressed in a lab coat, and had aged glasses that were barely hanging from the skull.

Marceline approached the skeleton...and then frowned.
Realizing that whoever this was died long ago. Making this so-called shelter their tomb.

It was a sight she was all too familiar with in her early life many, Many, MANY years ago.

Marceline then noticed something else...Around the skeleton's wrist was a strange device.
From Marceline's perceptive, it looked like the biggest wristwatch that she had ever seen.

Curious, she reached for the device and carefully slid it off the dry bones.
She then took some time to examine the device in her hand, staring at it's many gizmos.

Marceline then found some writing on it. It was faded...but she could make it out.

"p-pip...BOY?" spoke Marceline. "what a weird name to call something."

Marceline further examined the PipBoy...and noted something odd, yet Familiar.
Curious, she tugged at something...and pulled out a retractable cable.

"HEY!, I think this thing might open that door!" exclaimed Marceline, in realization.

Marceline then unlatched the Pip-Boy, and slapped it around her own wrist.
Upon doing so, it activated. and after a loading screen displayed text, the display came on.

The screen showed what looked like a Playlist of some kind.
After reading the text on the entries, Marceline soon realized they were audio recordings.

Still curious, the Half Vampire decided to play one.

The Pip-Boy played scratchy audio...and then a female voice spoke.


(("hello. I am Doctor Eileen Madison.")) began the voice.

(("I am- or, WAS a chief scientist of Vault-Tec, and would've been Overseer of this Vault.
but...I uncovered secrets of Vault-Tec that has made me question everything that I once believed in.

I am recording this audio journal to not only keep my sanity intact,
but to hopefully ensure that whoever finds this doesn't make the same mistake that I did.

The year is...(deep sigh) October 24th, 2077. and...the world ended YESTERDAY.

It happened so suddenly. There wasn't even a warning, no air raid siren to be heard.
One moment, I was watching my seven year old son blowing out the candles of his birthday cake...

And then...I saw the flash. and that horrible, rising mushroom cloud."))


Marceline froze, whispering the words: "the mushroom war", under breath.


(("-at that moment, my ONLY concern was the safety of my son. Aiden.

I snatched him up, and ran out of the house. Fortunately we didn't live too far from the Vault.
But as I drove us there, I could see more bombs detonating all over the city.

It took everything I had to not scream, It was like the whole planet was blowing up!

SOMEHOW we made it to Vault 110. a vault that was unfinished, but finished ENOUGH.
Me and my son were the only occupants. and...looking back. I regret not trying to save more people.

But I was scared, and all I could think about was protecting my little boy.
I will forever hate myself for leaving all our friends behind. and...Scruffy.

(*pause*)...If there is life after death, I hope they will forgive me.

although...I wouldn't blame them if they don't. I was part of Vault-Tec, afterall."))


With that, the recording ended.

Marceline paused, briefly looking back to the human skeleton that she now knew was Eileen.

Curiosity still holding her, Marceline selected the next recording and played it.


(("October 30th, 2077. Entry 2.")) spoke Eileen's voice.

(("It's been about a week since the bombs dropped. The first week of the new age.
I wonder if I should continue to track the time normally...or just reset everything to Year Zero.

(*pause*) no. I can't think like that. The world as I knew it may be gone,
but I can't lose hope at what Vault-Tec is SUPPOSE to be: To one day re-build the world.

I can't lose hope. I need to be strong...for Aiden."))


There was a brief pause, before Eileen continued speaking.


(("The transition hasn't been easy for my son. He still cries over what we lost.
He misses his friends who were at his birthday party. and...Scruffy, our pet dog.

(*deep sigh*) I wish I knew how to make his pain go away...I miss his sweet smile.

Halloween is tomorrow. and I know it's impossible to have a tradition Trick or Treating,
but I need to do SOMETHING to lift his spirits. to show him that we can't give up hope.

I will forever mourn those we have lost, but we can't feel guilty because we survived, and they didn't.

We need to keep living...for THEM."))


Marceline paused again, having a vague recollection on the term 'Halloween'

She knew it was a human festival from the time of the old world,
and to her knowledge was a 'celebration' of monsters like Demons, Ghosts and Vampires

(so needless to say, it was something that she was a big fan of.)

Marceline then played the next recording.


(("December 23rd, 2077. Entry 3.

It's been a couple of months now since myself, and Aiden settled into the Vault.
It could be because it is Christmas time, but Zaiden seems to be more cheerful.

I hope he likes the gift I have for him. I know I don't have the luxury of shopping,
but I was able to move some personal items into the vault before D-Day happened.

The gift I have chosen is a Keytar. It...belonged to Aiden's father.
I feel he would want Zaiden to have it (better than to keep collecting dust in storage.)

I'll have to teach him how to play it, but I have nothing but time now...Literally nothing but time."))


Marceline smiled at this "So, her kid's dad was a musician. Awesome!"

Marceline played the next recording.


(("January 1st, 2078. Entry 4.

It's the new year...which now has a whole new meaning now.

Usually New Year's is celebrated with optimism for a better future.
and while I need that optimism now more than ever, it is much harder now.

The Radiation Levels outside obviously hasn't gone down,
and despite the mandatory 180 Wait Period, I know they won't be going down anytime soon.

If only this vault had been completed fully...there might've been a chance.

GOD, why didn't I transfer to Vault 111 when I had the chance!? Things would be so much-

(*deep sigh*) never mind...I should be check on Aiden."))


Marceline raised an eyebrow, being left with even more questions.

She played the next recording. This one had a much later date.


(("March 14th, 2078. Entry...Five? y-yes, I think it's Five.

The Mandatory 180 Day wait period has now expired...but outside radiation levels are still too high.

Vault-Tec Protocol insists on waiting for the All Clear Signal.

But as all my monitoring of Vault-Tec Communications have been nothing but silent,
I dread that Vault-Tec itself is no more, and the All Clear signal will NEVER come.

If so...then it is all up to me now. Like it or not, I am the Overseer of this Vault.

I suppose it is a blessing in disguise that me and Aiden are the only ones here.
The Ration Stock was intended for a greater number of residents, so we have plenty to last...for now.

Speaking of, Aiden's skill with his father's keytar has progressed greatly.
I often hear music echo through these empty tunnels, which brings me comfort.

It often reminds me of when I was dating Aiden's father. I loved his music.

I miss him...so much. GOD, why did he have to be drafted into that horrible war?!
And for what!?, in the end NOBODY won it. We ALL lost...we lost Everything.

(*deep sigh*) I should get some rest."))


Marceline frowned, unsure if she should continue listening to these recordings.

But, she had come this far and couldn't bring herself to stop now.


(("October 22nd, 2083. Entry...oh, who cares anymore!

Tomorrow will mark the Seventh Anniversary of the day the world ended.
BUT, more importantly...my son's 13th birthday is tomorrow.

Tomorrow, my little boy will become a Teenager.

(*exhausted sigh*) this is not how I imagined such a milestone to take place.
He should have friends, maybe even a Girlfriend! I should be teaching him how to drive!

instead...we're still trapped here in this wretched vault!

Somehow, We still have enough supplies. but they won't last forever!
And the radiation levels are STILL too high to risk opening the Vault

DAMN YOU, VAULT-TEC! I hope every last one of you are BURNING IN HELL!

(*ragged breathing*) ...I should've done more. I should've done SOMETHING to stop this!
COULD I had stopped this? I have asked myself that question too many times to count.

I know it's too late to ponder the What If's. But I can't help but wonder...wonder."))


Marceline saw only a few more entries left. These were dated even further down the timeline.

Marceline felt she was reaching the end of this story, and dreaded it wouldn't be a happy ending.


(("November 12th, 20-(*violent coughing*), 2088.

ss-supplies are nearing d-depleted. and I-(*cough!, COUGH!*) I am unwell.

m-my son, n-now Eighteen, he thinks I have th-the flu. I can't tell him (*COUGH, HACK!*) the truth.

I...I have cancer. It's my own (*cough-cough*) f-fault. I left the vault for just a moment.
I th-thought my radiation suit would p-protect me...b-but I was wrong. (*loud cough!*)

outside radiation...ss-still too high. I ff-fear it won't lower for a...long, LONG time.

My days...are numbered. I have only...six more months.
b-but my son...I cannot leave this life knowing he may starve to death.

I must...I must use the time I have left to save him.

I already know...of ONE way."))


Marceline froze, immediately thinking back to her own mother.

she has also gotten sick, and was coughing alot when they traveled the wastelands together.

a tear then formed in Marceline's eye. She then selected the recording that read: [FINAL ENTRY]


(("february...14th. 20...89 (*cough-cough!*)

it's...valentine's day. and I...just performed my ultimate act of love.

I-(*cough-cough*), I sealed my precious Aiden in a cryogenic stasis pod.
like Vault 111, this place was supposed to study the science of suspended animation.

but this vault was...unfinished. there was...only one.

I...I lied to my son. I told him it was a decontamination pod.
that it would cleanse his body of any sickness that he might've gotten from me.

heh-heh...he actually asked me...why I wasn't going in first.

I hated...lying to him. but if he knew the real reason...he would never let me.
I hope he can forgive me...but I did what I had to do to save him.

My son...will live. He will live to see the outside world once it heals itself.

and yet...I still worry. My son will be all alone.

and even when the...ra-radiation fades. There will be...other dangers.
mutations...and even other survivors. They will not be kind to such a gentle soul.

(*pause*)...

whoever finds these recordings...please, PLEASE. take care my son.

the code...is my lullaby to him. it will...lead you to him.

(*raspy breathing*) please...watch over...my...suuuhhhh."))


As the recording ended, Marceline knew she had just listened to her final breath of life.
She turned back, and looked upon the woman's skeletal remains once more.

what had once been just some dry bones was now a person that Marceline actually felt sad for.

Marceline then looked back at the screen of the Pip-Boy, and saw a file that wasn't an audio file, but was labeled: [For Aiden.]

Marceline paused for a moment.

In the back of her mind, she heard dark voices telling her to just leave.
She had what she needed to escape this Vault. She could just leave.

but...there was someone here who was still alive. Someone who needed help!

'Not your problem', said the dark voice again.

But then another thought entered Marceline's mind...one that silenced the dark voices.


'It wasn't Simon's problem, either. yet he still took care of you.'


With that, Marceline pushed the dark voices back into the void where they belonged.

She then opened the file, where she saw song lyrics and musical notes.

"okay...I can work with this."

Marceline then drew out her Axe Guitar, and floated above the round desk at the center of the room.

She looked at the text on the Pip-Boy again, and then breathed out sharply.

Marceline began to strum the chords, creating a soft melody.
glancing at the Pip-Boy again, she started to sing in a soft tone.


"Remember me. Though I have to say goodbye.

Remember me, Don't let it make you cry.

For even if I'm far away, I hold you in my heart.

I'll sing a secret song to you each night we are apart."


Marceline paused to wipe a tear from her eye.

This song...though meant for Aiden, felt very personal to her too.


"Remember me, Though I have to travel far

Remember me, Each time you hear a sad guitar.

Know that I'm with you the only way that I can be.

Until you're in my arms again...Remember Me."


Once Marceline hit the final note...a loud beep was heard,
followed by the floor underneath the desk moving with a rumble, revealing a hidden passage.

Marceline wipe one last tear away, and holstered her Guitar back behind her back.
She then lowered and floated down the passage and approached a door that opened up.

Marceline soon realized that the door was an elevator of some kind.
Without hesitation, she entered the lift and stood by as it closed up and went down.

Once the Elevator stopped, it opened up to reveal a long up ahead.

Marceline sighed, and started floating again. she glided across the long tube, and finally came to another sliding door.

"my gob, these doors..." grumbled Marceline.

As she opened the doorway, Marceline entered a large chamber that was FREEZING cold inside
(in fact, it was so cold that Marceline half expected to encounter the Ice King in here.)

Marceline then spotted something at the center of the room. Approaching it, she found it was a machine hooked to what looked like a space aged coffin.

Realizing this was the Cryo Pod, Marceline flew over and faced it.
There was a glass window fogged with condensation, but she could make out Someone inside.

Marceline wiped the glass...and saw who was inside.

It was a male that looked around her age (*LOOKED* being the keyword there)
with messy dark brown hair, and Caucasian skin that looked pale due to being frozen.

"so, you're Aiden...heh, gotta say: you're not bad looking." spoke Marceline, smirking.

Marceline's smile then disappeared. she knew that once she let Aiden out,
he would be VERY confused, and the first thing he'd want to know is where his mother is.

the half-vampire shivered, not sure how she was going to explain to this boy
that his mother was not only dead, but has been dead for nearly two centuries.

"come on, marcy...you gotta do this." whispered Marceline to herself.

Marceline looked to the control panel of the Cryo Pod.

She zeroed in on a big red button, took a deep breath...and pressed it.

There was a hiss, followed by the sound of cracking ice.

Marceline looked back to the pod's window...and watched as Aiden opened his eyes, and gasped.

[To Be Continued..]


[Author Notes]

alright...buckle up. There is alot to unpack here.

With the Free-to-Play Smash Bros-like game, Multiversus
recently adding Marceline to it's fighter roster this December.

I found myself liking the character,
and wanted to make something creative based on her.

Now let me make clear: I have NEVER watched Adventure Time.

It was a show that I dismissed as "too dumb"
when it first came out, and I had all but ignored it.

But with all the clips on YouTube that pop up,
other people's fanworks, and the new show on HBO MAX.

I have come to realize that I was wrong about Adventure Time,
and I am beginning the process on catching up with it.

So, while I still have ALOT more to learn.
I feel I know enough to get started on this test story.

What you are reading here isn't a full story...yet.
It is more of a "Pilot" for what may be a full story

(and of enough readers like it, I may put more time and effort
into a full, multi-chapter story based on this concept.)

I tried to have this be a single page story,
but once again, I have to split this into multiple parts.

Said concept is very simple: It's a crossover between Adventure Time and Fallout

(which is a VERY popular crossover choice in the fandom
since Adventure Time shares alot in common with Fallout...if you can believe it.)

Basically, this is Marceline and a Protagonist
in the Fallout Wasteland.

For Adventure Time fans, this is a Role Reversal
of the 'Simon & Marcy' episode

(only now Marceline is the Protector, taking Simon's role.)

and yes, I do intend this story to be a Marceline x OC pairing

(the possible full story may also have "Bubbleline" in it,
but for THIS pilot, It'll just be Marcy and Aiden for now.)

Anyway, please by kind with your reviews
as this is my first Adventure Time story.