They were dressed, sitting at the kitchen table, eating leftovers when Jake came home; Marcy wore a pair of Finns sweatpants, and a faded grey hoodie that was too baggy on her. Her hair was pulled into a ponytail; she looked right at home, almost as if she lived in the treehouse. The dog walks through the front door smiling, until he sees Finn. The human stands, shaking his head.
"Jake."
"I don't wanna do this again, bro. I'm goin upstairs."
"No, Jake, wait. can you listen to me, for just a second?"
The dog crosses his arms.
"What?"
"I'm sorry."
"Sorry won't save your life against the Litch."
"But it will save our friendship."
"Man, that's corny."
"And being mad at me is stupid, especially if I might not be around much longer."
The dog sighs, but holds out his hand, and the two of them shake.
"I forgive you, Finn. and I'm sorry I was such a jerk earlier."
"Dude, it's fine. you're just worried about me, I get it."
"Then why do you still want to-"
"No, Jake. You're right, we're not doing this again. The discussion is over."
"Fine."
They hug, and Jake pats Finns back.
"This is messed up, dude."
"I don't wanna think about it anymore."
"But Finn, what if something-"
"No more, Jake."
"Urghhh..."
The dog huffs, and crosses his arms. He puffs up one of his hands, stretching it, and pokes Finn in the chest.
"You'd better come back, Bro."
"I will."
"Promise?"
Finn doesn't want to lie to his friend, so he simply shakes his head. Marceline finally speaks up.
"You guys wanna, er... watch a movie, or something?"
She chuckles nervously. Jake turns to face her, eyeing her up; the way she wears Finns clothes, the way she looks at him, confirms the dogs suspicion.
"I'm guessing you two are like, a thing now."
Finn nods, grinning, and Marcy stands up to hug him protectively.
"Yeah, bro, and it's pretty math."
"Finns my boyfriend, dude."
He walks over to the both of them, looking very stern, when suddenly he breaks into a huge grin and pulls them both into his arms, making it a group hug.
"Finns right, that is math! Marceline, this means we're like, family or something now."
"I guess so, dude. You still gonna be a total weenie around me?"
"Nah, you're cool by me, vampire or not."
"Really?"
"Well, yeah. If Finn trusts you, and likes you, then... I trust you."
The vampire smirks, and decides to call his bluff; she bares her fangs and her eyes flash red as she hisses at Jake. He screams, pulling back from the hug and falling on his butt.
"You're sill a weenie."
"That was mean!"
"It was a joke, dude. Besides, you're totally still scared of me."
"Okay, maybe a little..."
They all laugh, and end up putting in a movie on BMO.

Jake sits in the easy chair, snoring, as the end credits of Heat Signature 3 drift down the screen; Marcy is cuddled up to Finn, in his lap on the couch. They're not talking, or kissing, or even moving, they're just... there. Holding each other as he looks down into her eyes, his fingers twirling her hair up and playing with it wordlessly as they smile... this moment, to Finn, feels genuine. Like they're a real couple.
"Finn."
He pokes the tip of his nose against hers.
"Hmm?"
"It's late."
"Hmm."
He doesn't let go, and in facts tightens his grip around her.
"Finn, I should-"
"Stay."
"What?"
He pulls her closer, closing his eyes with a sigh as he buries his face in the crook of her neck... the sweat shirt already smells like her.
"Stay with me."
The idea of her leaving, at this moment, was unbearable to him; he knew that once she was out the door, he would be a nervous wreck... as far as he was concerned, tomorrow he would be going into the portal to face the Litch... and despite his reassurances otherwise, he knew their time together was most likely short. So he holds her, taking in that sweet, strawberry scent, mixed with the slightest tinge of... dust, like something old, was the best way to describe it. But it was rich, and comforting, and so very... Marcy.
"What about Jake?"
"He'll stay in the chair until he wakes up tomorrow all sore and then stretches it out."
"He's done this before?"
"Usually once a week when we have movie night."
"Oh."
Without another word, she leans up, and they try not to slurp or suck or make noise as she kisses him hungrily, loving his lips, the way he tastes, the way his fingers clench in her hair, the way his stubble scratches across her chin... him. She loved him, and tomorrow she might... lose him. But no matter how hard she tries, and Jake too, they can't convince him. So she stays quiet, just letting thier tongues dance and run against each other as she surrenders herself to him, feeling, at this moment, like his arms were... home. He's the one who pulls off, and she tries not to sigh too hard.
"We should get some sleep."
"Yeah."
"I can, uh... sleep on the couch, or something..."
"Nah."
And then he's lifting her, like a princess, carrying her towards the stairs as he holds her close to his chest.
"Marcy, I love you."
"I love you too."
"I love you more."
"You're a dweeb and I love you way more."
"You're a goof, and my love for you is stronger than a thousand suns."
"I'm immortal, and my love for you will go on forever, even when the sun is gone."
They go on like this as he carries her to his room, until finally they reach his bed and he puts her down, ever so gently as he crawls beneath the blankets with her. They look at each other, smiling like loons.
"I never thought we'd-"
"Neither did I."
"But we are."
"Yeah."
And then she's wriggling out of his clothes, sliding the sweatpants down and the hoodie off, and he blushes hard.
"What are you do-"
"Shh."
"But I-"
"Shh. It's not what you think."
"O-Okay..."
So he undresses as well, and then they're both laying there, facing eac other, about a foot apart as she smiles at him.
"Why did we-"
"Shh."
"But Marcy I-"
She places one of her cool, delicate fingers over his lips, silencing him as she slithers into his arms and entangles their naked bodies. As she turns around, her back against his chest, and curls her body to fit his, he sighs... it does feel nice.
"Oh."
"See?"
"Yeah. This is... great. And your skin is really soft."
"Thanks. You're all warm, and stuff. It's nice."
"Thanks."
"Finn?"
"Yeah?"
"I don't want you to die."
"I don't want innocent people to die."
"But you don't have to be the one to-"
"Yes, I do. And you know exactly why."
"I know."
They sit there in silence for a while, just enjoying the feeling of each others bodies, treasuring their time together. Finn files this away in that special part of his brain reserved for his best moments, the ones he thinks of whenever he's feeling really down... lately, all of those times, those memories, he's made with her. The thought makes him smile.
"I'm sleepy."
"Me too, hun."
"Woah, really? Hun?"
"Yeah dude, get over it."
"Sure thing... Mar Mar."
They both snicker, and he kisses her neck.
"Goodnight, Finn."
"Goodnight, Marcy."
"I love you, Dweeb."
"Love you too, goof."