This is set post-season 5, but I haven't seen any of season 6 yet (It's not airing in Britain, to my knowledge), so it's best to think of this as a 'what if?' rather than trying to be canon.
At first, when the door opened, Sam didn't look up. Dean wasn't supposed to be back for hours yet; maybe he forgot something.
He was on his feet before he was even aware he was moving; the instant recognition of that voice and what it meant.
"No! You're in Hell! I took you there myself!"
Jessica didn't move, standing in the doorway with her hand still on the door handle.
Sam felt the fury, the impossibility of it all rising up so fast he didn't know how to hold it in. Lucifer couldn't have gotten out, there was no way, so how was he here now, wearing the shape he knew would torture Sam more than anything dreamt up by all the legions of the pit.
"Stop it, just… Stop. Stop it. Stop looking like that. Please."
Even if it wasn't Lucifer, some other demon or sonofabitch that thought it could survive going up against Sam Winchester wearing the face of his murdered lover, whatever. They were toast.
He didn't have the Colt to hand, but there were plenty of other weapons, and he grabbed at the bag now, never taking his eyes off the figure in the doorway. Why her? Why did they always have to choose her?
She still hadn't moved. She didn't, for once, look the same as when she'd died. Her hair, her beautiful hair, was cut shorter, straightened and tinted a rich brown, and she was wearing clothes much like his own; jeans and a long-sleeved shirt, as opposed to the cute outfits she'd favoured in life. A shoddy reproduction, then, made from someone else's memories instead of the ones that burned inside his brain.
"It's me, Sam. Really me. It's Jess."
"What, do you think I'm stupid? I know she's dead; I was there!"
"So was I."
There was something in her voice, the intense sadness in her face, that made Sam hesitate. He wanted, so badly, for this to be real. But he knew it couldn't be.
"I remember it all; Brady came over, said he needed someone to talk to, but it wasn't Brady. His eyes went black, and the next thing I knew, I was on the ceiling and there you were, Sam. You came in and there was blood and fire. And I died."
Sam's hand was shaking so much he could barely hold the gun.
"And then I came back."
"What do you mean? Came back?"
"I was away for a long time."
Jess' eyes were holding his own steadily.
"And it took a lot, but I made it back. I've come back, Sam. Come back to you."
Despite everything he'd seen hunting, everything he knew, Sam felt himself start to slip. He wanted to believe her, god knows he did. He still had nightmares about being forced to watch her burn before him, how he'd failed to save her.
"That's not possible."
"Why not, Sam? You came back. More than once. So did your brother; you believed him."
"Maybe because no demon, or fallen angel, or whatever the hell you are, ever put on his shape just to fuck with me, to try and trick me. It's always you, Jess, when they want to break me. And I won't let anyone do that again."
"You want proof. That's okay; I would too, in your place."
Jess went over to the glass of water sitting on the table by the door and passed a hand over it, her other hand fingering the crucifix she wore around her neck, reciting a few phrases in Latin, words Sam recognised as a kind of blessing, although he'd never heard Jess say a word of Latin in all the time he'd known her.
Then she picked up the glass, and drank from it.
"See? Holy Water, and it doesn't burn me or make me shrivel."
She rolled up a sleeve to show him the tattoo marking her left forearm; an anti-possession symbol, much like his own.
"If you want to pour out a salt circle, I'd be more than happy to step over it if you want me to, to prove I'm human. That I'm really me."
Sam's heart was beating so hard, it hurt. He gazed at the face of his five-years-dead girlfriend, as if by staring hard enough he could read her mind, see if she was telling the truth.
"I had help."
And there was another figure in the doorway behind her, one Sam had had no idea was there; another woman. She was older, maybe fortysomething, attractive in a severe way, with grey eyes and blonde hair pulled back into a bun, dressed in an immaculate white mac that reminded Sam of Castiel.
The penny dropped.
"Oh my God!"
The woman smirked.
"Not quite, kiddo. But close."
"You – you're an angel?"
"My name is Sariel. I have been walking the Earth for many years now, and part of my task here, among other things, is the protection and guidance of one Jessica Lee Moore."
She laid a familiar, almost motherly hand on Jess's shoulder.
"For a while, most of my work involved keeping her away from you, but Jessica doesn't give up easily, and eventually it was decided that you should be allowed to meet again."
Instantly Sam was engulfed in a whirl of emotions; mostly the beginnings of acceptance that the girl in front of him was really Jess, his Jess, the girl he'd once thought he'd marry, spend his life with and behind that, coming in really, really fast, was an intense rage at the angel's words.
"You mean you've been keeping us apart? How long?"
"I came back about the same time you did," Jess replied.
"About a year ago. I tried for a long time before that, but they wouldn't let me."
"So why now?"
Sam managed to keep the fury inside, with a colossal effort, holding it back because he knew if he lost it now, he might never get to hear the answers he needed, that Jess might vanish as abruptly as she arrived.
Sariel gave him a very even, very steady look.
"After the events of the Apocalypse, things changed; you're aware of that. Both on Earth and in Heaven. Certain - differences of opinion that were resolved."
There was a pause, and Sam couldn't contain his impatience.
"Once your path had been laid, your choices made, certain happenings in the run-up to those events came to be seen in a different light. One of those was how Jessica here died. Before you confined Lucifer to the Pit, the opinion of those of us involved was simply that she was another victim, one of many, and that therefore it was natural. Regrettable, but natural."
She amended, seeing the way Sam's nostrils flared in anger at her words. She might know the gun he still hadn't put down couldn't harm her in the slightest, but this boy and his sibling had destroyed archangels, and thus should not be underestimated.
"Whereas now, we came to see that Jessica's death could be viewed as a sacrifice; part of the plan created around you by Lucifer and his underlings, and thus… reversible."
Sam looked over at Jess, who had a small, sad smile on her lovely face.
"I know, it sounds crazy. But not half as crazy as everything else, huh?"
"Have you – you were in Heaven?"
"Did we ever meet? I don't remember much about when I was there."
"Meet? You don't meet anyone in Heaven. Or at least, I didn't. But I have been watching you."
All of a sudden, Sam felt a desperate shame at the thought of Jess witnessing the things he'd done since losing her. Not just bringing forth the Apocalypse, but everything. All the things he couldn't tell her about when she'd been alive before.
Killing demons, vampires, ending ghosts and spirits. Fighting with his brother, his father; letting Dean go to Hell for him.
Jess took a step forward and finally, she touched him, her hand on his arm.
"It's okay, Sam. I understand."
"Understand? No, Jess, you can't."
"I said it's okay. I … see things differently now. I'm still me, but I see the wider world."
Sam met her eyes again and felt tears well up in his own for what felt like the first time in years. He didn't usually cry; anger had been his first reaction to everything in such a long time.
"I got you killed, Jess. Because of who, what I am. Because I lied to you. How can that be okay?"
"Because it really is."
She put her hands either side of his face and it was Jess, his Jess, there in front of him and any last doubts withered and died. She was different, in many ways, but then so was he, now, and it was undeniably her. Not even when Dean had come back from Hell, appearing in front of him in such a similar manner, had it felt like this; every thought, worry, agony of guilt flooding through him.
"None of it was your fault, Sammy. You didn't mean it to be that way, and I know you were trying to protect me."
"It doesn't matter. You saved the world, in the end. Doesn't that count for anything?"
Nothing could ever take that sensation of intense culpability away, but having her back – maybe that would be a place to start.
"What – what have you been doing, since you came back? For a whole year."
Jess' expression grew more serious.
"Hunting? Oh Jess - no."
Sam's heart strained within him. Not only had he gotten her killed, now he'd turned her into a hunter? Surely there was nothing more he could do to destroy the girl he loved?
"It was part of how I got them to agree to let me return – if I came back to Earth, then I would become an instrument of Heaven, and I wanted to start by destroying evil. So I'm learning to hunt."
"I learned from the best; watching you and your brother. I met a few other hunters too. And Sariel helps me with the lore, the Latin and Enochian, things like that."
"But Jess – hunting. It's not a life. It'll just get you killed again."
"I told you I'm watching out for her," Sariel spoke up.
Sam had forgotten she was in the room, so intent was he on Jess.
"I have a vested interest in this one, and I intend to keep her alive for as long as I can."
Sam turned his face toward her, his eyes cold.
"Until you're given orders to keep us apart again? Or to let her be 'sacrificed' for some other demon's plan?"
The angel didn't react to his vitriol.
"All prophecies that I am privy to ended when the Apocalypse did. While I won't pretend there are no more plans in motion, there are none that involve Jessica. As for you… well, you Winchesters are the gift that keeps on giving, aren't you?"
"Sari, would you give us a minute?" Jess asked, and the angel popped out of existence, leaving the couple alone together for the first time in more than five years.
So much had happened in that intervening period, and both were aware of it. If Jess hadn't been killed, Sam thought, they'd be married by now, living in a white-picket-fence house in the suburbs with a dog and maybe a couple of kids. He'd be a lawyer and -
"How are you living? I mean, hunting doesn't exactly pay…"
"Waiting tables. I do temp work inbetween jobs, mostly. Tend a little bar, too."
"Waiting tables? Jess, you were a Philosophy major."
"Exactly. I'd probably have ended up doing that anyway. And besides, I can't live the way I did before – no-one's supposed to know I'm back."
"Your parents don't know?"
Jess shook her head, clearly upset by this but keeping it under control.
"They can't. I haven't told anyone my real name and I had to sort of re-invent myself. Which seemed appropriate enough."
"So why can I know? You said they wouldn't let you see me at first?"
"Like I said, no-one's supposed to know that I returned; I can't just walk around telling people I came back to life after being dead for four years. You're the only person who'd understand, and I think they didn't want us to meet at first until they were sure what I'd do. The whole thing about no more prophets is scaring them. Sari finds it hard to cope with no future knowledge, that much I'm sure of."
Sam could understand that; he remembered how hard Castiel had found it to cope with being cut off from Heaven, not understanding what was going on and trying his best to make his own decisions after millennia of obeying orders. Didn't want to think of a whole garrison of angels in that state.
"But I wouldn't let it go. I watched you for a long time, and I couldn't stay away any more. I just about drove Sariel crazy, but I think she understands. She's been living as a human for a lot longer than most angels."
Sam found it hard to care about angels right then.
He stroked the back of his hand down Jessica's face, trying his hardest to take it all in. He'd never expected to get her back, not ever. Maybe once he'd thought they'd be reunited in Heaven, but his experiences of – that place – had changed his dreams so much he'd all but given up hope.
He pulled her close, wrapping his arms around her, letting himself remember how much he missed her, all the feelings associated with his lover he'd been struggling with for five years. She fit into his embrace perfectly, and he couldn't hold back the tears any more.
"I missed you. God, I missed you so much. I got so lost without you."
"I know, baby."
Jess let him rest his head on her shoulder, stroking his hair.
"I missed you too. Every day. But that other stuff; none of that matters anymore, Sam. I'm here."
She kissed his cheek and he turned his head to meet her lips and they kissed like two broken halves of something fitting back together, clinging to each other out of a desperate need. Neither was the same as they had been when they were just another young couple back at Stanford, and the desire to reconnect was overwhelming.
The kiss became more and more intense, their hands moving over the other as if exploring something new. Jess was stronger now, Sam could feel from the way she pressed herself against him; he remembered how she had taken classes in self-defence back then. She was far tougher now, the muscles in her arms better developed, but then Jess was thinking the same about him. She didn't know the jokes Dean had made about how out of shape Sam had gotten at college, and how he'd kicked it up a gear since resuming hunting, but she could feel his strength as he picked her up, her legs wrapping around his waist as he moved them over to the table, never stopping kissing her.
She tugged the short-sleeved shirt from him, revealing a scarred, tattooed torso that was so different from the one she remembered, her fingers roaming over his skin almost hungrily. When she and Sam had made love before, it had been just that; making love. That wasn't to say there hadn't been passion, but there had never been this aggressive intensity before, this need and it was overwhelming her.
"Sam," she moaned, his hands stripping off her t-shirt, unsnapping her bra and caressing her breasts, sending the most powerful sensations coursing through her.
"I need to tell you… I've done things. Bad things."
"I don't care," Sam replied, kissing his way down her neck. There was a finality to his words, but Jessica persisted.
"I killed someone. They were possessed, and it went wrong and I got him killed, the man the demon had taken over."
Sam paused his exploration of her just long enough to look her deep in the eyes.
"Jess. I don't care. Nothing you've done is so bad that I would care. You know everything I did, and you're still here."
Every time he touched her, he felt like it was eradicating his past, everything he'd done, every remaining trace of that manipulative demon bitch on him dissolving.
"I just… I needed to tell you."
His mouth came down on hers again, his hands unzipping her jeans, pulling them down over her hips. Jess put her arms around his neck, raising herself up so he could strip off her jeans, her underwear going along with it until she was naked beneath him, her legs circling his waist again as he kicked off his own jeans.
Jess clung to him, calling out his name as he pushed inside her, his face pressed into her neck, her hair and they moved together.
It had been a very long five years, and they had a lot of making up to do.
Disclaimer: Um, Sam and Jess aren't mine. Obviously.
In case you don't already know, 'volver' is Spanish for 'return', inspired by the Pedro Almodóvar film of the same name.