AN: Leah is an OFC from previous stories in the Wyoming!verse. Basically, she's a good friend of Sam's, they have sex on occasion, but they're not a full-blown romantic couple. She's super supportive of Dean and Sam's partnership/the Winchester Family of 3.
He's walking through the house—his and Dean's house in Wyoming—but it's empty of furniture and decoration and the Winchesters' personal possessions. The windows are open, curtains floating out of them like the empty dresses of dead women. He calls out for his brother but no one answers. He calls out for Castiel, but the angel doesn't appear. As he approaches the front of the house, he notices the front door flung wide open, the jamb framing a blonde woman sitting at the top of the porch steps with her back to Sam.
"Leah?" he says to her, as he reaches the doorway.
She looks over her shoulder at him—but it isn't Leah.
Sam's breath catches in his chest and he freezes. "Jessica."
She smiles at him and turns around again to face the landscape sprawling before the house.
Sam hesitates, then musters up the courage to step outside and join her. He sits down next to her and stares, not knowing how to feel. She looks exactly the same as she did when he last saw in their Palo Alto apartment, twenty-two years old and too pretty to live. She's wearing a floral skirt, button down blouse, and her worn out pair of blue Converse. She looks peaceful, like she could sit here on Sam's porch forever in perfect contentment.
"What are you doing here?" Sam says.
"Someone had to come get you," says Jess. "You deserve to know the truth, Sam."
He shakes his head a little, frowning. "What truth?"
Jess looks at him, her eyes gentle, reaches out and lays her hand on his knee. "It's not real. You've been making it all up because you don't want to live without him."
"What are you talking about?"
"This house in Wyoming. This whole life you think you have. It's a dream, Sam. Everything since Dean's death has been a dream." She squeezes his knee just a little. "He's in Hell, Sam. He never got out. And you couldn't live with that."
Sam just looks at her, brow furrowed, the warm weight of her hand familiar and unfamiliar, the emptiness of the house behind them like a fire burning a hole through his heart.
The whole world is silent, as if he and Jess are the only two people in it.
She takes her hand away and looks forward again.
"No," he says. "That's not possible."
The corner of her mouth barely curls, a wistful suggestion of a smile.
He couldn't have been asleep the last twenty years. The almost-Apocalypse, Lucifer possessing him, his time in the Cage, Leviathans, Bobby's death, the three trials, Castiel, Kevin, Charlie, Amelia, the Bunker, the Men of Letters... They must've been real.
Dean. All this time.
Sam twists around and looks back into the house—still empty, the long corridor reaching deeper than he remembers. He looks into the front lot again and realizes the Impala's missing.
"I'm sorry," Jess says. "You were going to figure it out eventually. I didn't want you to be alone when you did."
Sam's heart starts beating too fast. He's shaking his head and leaning away from her, mind racing. If his life isn't real, what is?
He's about to bolt, about to start screaming for Dean, but Jess reaches up and presses her hand to his neck, fingers slipping into his hair, and kisses him. He can taste her strawberry lip balm, smell her floral perfume and the sea in her hair.
For a split second, he's a college kid again, his whole life ahead of him. He's going to ask her to marry him. He's going to leave his past behind. He's going to live a happy, normal life. He's going to stay innocent.
She pulls away from him.
Leaves him alone.
Sam wakes up in the dark, breathless. He's in his room at home—in the house he shares with his brother, twenty-five minutes outside of Big Piney, WY. He turns on his night table lamp and looks around the room. Everything's exactly as he left it when he fell asleep. He turns the digital alarm clock toward him: four twenty-seven AM.
Sam only lies there in his bed for about thirty seconds before deciding that no, he can't just roll over and go back to sleep. He throws back the sheet, comforter, and blanket, swings his legs over the side of the bed, and slides his feet into his slippers.
The house is pitch dark except the milky light of stars and moon sneaking through the windows. Silent. Warm. Sam touches the walls to test their solidity, feels the floor solid under his feet, sees the door to his brother's room across the corridor cracked open and almost doesn't want to see to the other side, in case Jess was right.
Sam pushes the door open and stands in the doorway, looking at Dean's silhouette in the bed. A minute or two passes, and before he can turn around and go back to his room, Dean stirs with that sixth sense they both have about each other, after decades of sharing motel rooms. He sits up and says, "Sam? What is it?"
Tears rush into Sam's eyes at the sound of Dean's groggy, rough voice. He feels stupid for being so afraid, for getting this emotional, all because of a stupid dream. He's had enough nightmares in his life that he should be used to them. He should be able to shake them off, and most of the time, he can.
"Nothing," he says, the sound of his own voice weak and strange. "Sorry."
He starts to turn around and shut the door with him.
"Hey," says Dean, a little more alert. "C'mere."
Sam pauses and hesitates, just staring into the darkness of Dean's room with his hand on the door knob. "I was just checking on you, that's all," he says. "I'm going back to sleep."
"Dude. Don't make me chase you."
Sam doesn't actually want to go back to his room, so he caves without any more fuss, sitting on the empty side of Dean's bed as his brother moves over to make room for him.
"Bad dream?" Dean says, after a moment.
Once in a while, Sam wishes they didn't have intimate knowledge of each other, borderline telepathic connection, whatever internal tuning fork that endows them with the ability to just know what's going on with each other all the damn time. But it's not often, not since they retired here and learned to just give in to their relationship. Sam's come to appreciate the fact that there's not a whole lot of guess work between him and Dean, regardless if it means that most of their feelings, thoughts, needs, and desires aren't private even when they're unvoiced.
Dean sighs behind him, a sound of resignation. If you don't want to tell me the details, fine.
Sam's embarrassed he had the dream at all, doubly embarrassed that it's this disturbing to him. He'd rather have a flashback to Hell.
Dean taps Sam's side with the back of his hand. If you're going to get in, get in.
Sam lies down under the covers and waits for Dean to speak or roll over away from him. Instead, Dean stretches out his arm toward Sam, holding it up off the bed. Sam looks over at him and doesn't respond. Dean waves his hand in the air, beckoning toward himself. Sam closes the space between them and presses up against Dean's side, curling on his own. He rests his head on Dean's shoulder and chest, feels Dean's arm bend around his back as he drapes his own arm across Dean's belly.
Sam closes his eyes and exhales, a good-sized chunk of his anxiety evaporating. Dean's warm and firm next to him, chest rising and falling with his breath, heart beating not far from Sam's ear, and Sam can smell him, that scent belonging to Dean's skin that Sam has associated with home and safety since he was an infant.
Dean's head flops to his right on the pillow, chin resting against the top of Sam's forehead and breath blowing through Sam's hair as he exhales.
Sam lies awake, holding onto him, after Dean's slipped back into sleep—and he realizes that if Dean had never come back from Hell, Sam wouldn't have lived this long at all. He would've found a way to join his brother.
Better an eternity on the rack with Dean than a million years in Heaven alone.