A/N: Thanks so much to those who have reviewed! This is approaching its end (one chapter after this one) and the whole warning about character death applies strongly to this chapter. All other comments and disclaimers posted in the first part.

Chapter 4

Dean hovered over Sam, his hands uncharacteristically fumbling as he tied his brother's hands together behind the chair.

"Make sure they're tight," John ordered. "It needs to believe in Sam's vulnerability in order to risk showing itself."

Dean pulled the bindings tighter; Sam stifled a grimace as the rope cut into his wrists.

"There," Dean said, examining his handiwork with satisfaction. "Should be no way to get out those puppies."

Sam tested them, trying to jerk and wriggle his hands. "Yeah, they're good," he said. "I'll have no feeling in my hands after five minutes, but they're good."

"I can loosen them some," Dean offered, studying his brother in the dimly lit room. They had carefully lit all the candles around the edges of the room before situating Sam in the center, bound to the chair.

"No," Sam replied quickly with a shake of his head. "They have to be tight."

There was a pause. "Man, I hate leaving you like this."

Sam grinned. "You worried about me?"

"Nah, I just don't want to have to save your ass again."

"If I remember correctly, I've been the one rescuing you lately. Remember the scarecrow? And the psycho hick hunters?"

"Yeah, whatever, dude. Just trying to make you feel useful."

The joke settled uneasily into the empty room.

Dean looked nervously at his brother. "You sure about this, Sammy?"

Sam chewed his lower lip before giving a half-smile. "Yeah," he said. "This has to end, Dean. It will destroy us all if we don't."

Dean tried to look as resolute as Sam sounded. "Yeah, I know. It's just--I mean--"

Dean's attempts to express concern were pathetic, and his awkwardness amused his brother. The humor was a dark, though, and the Sam relished the sentiment that Dean could not quite bring himself to give voice to. "It's going to be okay. I mean, you're going to be on the other side of the house--you and Dad. With the two of you, how could anything possibly happen to me?"

Dean let out a nervous laugh, but couldn't look at his brother. "Right."

John's voice came from the hallway. "Dean, you done in there?"

"Yeah," Dean called, steeling his voice again. Then he looked back at Sam. "I guess this is it."

"Guess so."

"If you need anything, if you feel like something's not right, you yell, okay?" Dean's face was serious. "And I will get you out of here."

The certainty in his brother's voice eased Sam's discomfort. "Thanks."

"Okay, then," Dean said, turning to leave.

"Hey, Dean."

"Yeah?"

"If something goes wrong--"

Dean shook his head. "Don't talk like that, Sammy."

"It's just--"

"Sammy."

"I just want you to know that it was worth it. Everything." The words came out in a rush. Sam needed his brother to hear them, even if Dean didn't want to. "I know I gave you a lot of hell growing up, but I never regretted any of this, Dean." Sam swallowed back an unexpected hitch of tears. "These last few months with you--they've been the best time of my life."

Dean felt the betraying sting behind his eyes and he forced a laugh. "Gonna choke on feel-good here, then who's going to save you, little brother?"

Sam laughed weakly. "Sorry."

"Well, not long now," Dean raised his chin, willing stoicism for them both. "We'll be right here. But watch out, ok, Sammy?"

"You, too."

Dean gave his brother one last look, taking in the ropes that were bound tightly around his chest, his legs, his arms. Sam looked so alone, so young on that chair. The room was not large, but it seemed too big, too open. A shudder traced up his spine.

"Dean!"

His father's voice broke his reverie. Turning away from Sam, he exited the room, willing away his anxieties and trusting in his father's plans.

Sam watched Dean go, feeling his absence like a hole in his stomach. He shifted uneasily in the chair, wishing suddenly that they had at least picked one with padding, one that wouldn't make his butt go numb so quickly.

Then again, part of him wished his entire body were numb so he couldn't feel that fear and anticipation that threatened to overwhelm him.

He didn't like being the bait. Not that he didn't want to do his part, but he hated feeling so useless, so immobile. The vulnerability was unsettling. And the feeling that something was wrong with this - majorly wrong - had not left him.

He twisted his hands, instinctively pulling against the binds until he reminded himself that the goal here was not to escape. His only task was the hardest one of all - to wait. He took a deep breath and tried to clear his mind. He had to be ready for what was coming, ready to do his part. He was not going to bail on his family this time.

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Dean followed his father to the other room, images of Sam flooding his mind. He didn't doubt his father, but damn, it had it been hard to leave Sam alone - alone and exposed. It went against every instinct he had. And not being able to see Sam, knowing that he would have to wait, a whole house away from him while they performed the ancient ritual that would draw the demon to his brother . . .

It took every ounce of resolve he had to not turn around right then and end this.

His father must have sensed his turmoil. Before they reached the other room, Dean felt a firm hand on his shoulder. His father turned him so that they were eye to eye.

"Before we do this, I need to know. I need to know if you'll follow me no matter what."

Dean looked confused. "What do you mean? Dad, you know I'd follow you anywhere."

"When push comes to shove, will you be by my side?"

"Of course, I--"

"Against anything." John's voice was low, his stare deadly.

Dean's breathing quickened. His father was focused and strict, but he had never seen him quite so dark, so terrifyingly determined. "What do you mean?"

"If you had to choose, Dean--me or Sam--who would it be?"

The question cut at Dean, touched him deep within the darkest places of his mind. The confusion on his face was laced with fear, laced with bated anger. "Dad?"

A sad look spread across John's face. Dean's expression was the only answer he needed. "That's what I thought," he said with a sad shake of his head. "I'm sorry, Dean."

Before Dean could react, his father swung his gun against his head. He tried to move, but he wasn't fast enough.

John stared down at his son, the rifle in his hand now stained with his blood. "I'm doing this for you."

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Sam curled and flexed his hands, trying to keep the sensation intact. The candles were already burning low, and Sam wondered how much longer they were going to have to wait. We should have put a clock in here.

Then he heard it--a small creak from the doorway. He looked up, watching as the door swung open to blackness. He tensed himself, prepared for whatever he might see. A dark figure loomed in the entrance.

"Dad." The tension diminished into a smile. "You scared me."

His father didn't answer. John took a slow step into the room, his face obscured by the flickering shadows of the candlelight.

Sam's smile faded as he took in his father's disposition. "Dad?" The tension came back with vengeance.

His father moved forward, his movements purposeful, deliberate.

Sam's heart began to race. He couldn't think, he couldn't see, he couldn't hear. "Dad?" Something was wrong--something was very wrong.

His father approached him, now standing in front of him. John ran a gentle hand through Sam's hair, resting on his cheek. "I'm sorry, Sammy."

Sam's eyes finally focused. His father was crying.

All of the fears and doubts Sam had kept at bay came rushing back, and he knew. He knew, but he couldn't accept. "Dad, what is this? What are you doing? Where's Dean?"

John said nothing, but merely shook his head. He pulled something from his pocket, laying it across Sam's knees. Sam looked down, bile rising in his throat as he realized it was a knife.

"Dad, please." Sam's breathing hitched, the effort to stay calm nearly too much for him. This can't be happening. "Don't do this. Whatever you're thinking, it's not true. It's not real."

"But it is real." John's quiet conviction was Sam's undoing. Panic set in as he realized that John was not to be dissuaded.

"It's always been you, Sammy," he said. "You're the thing I'm hunting. You're the thing I've spent my life trying to destroy. You're the reason for all of this. I think I knew it all along but I just couldn't see it--I didn't want to see it--"

Sam's eyes stung and he pulled frantically against his bindings, wishing he had let Dean loosen them.

"It's you, Sammy. The darkness is after you, it's in you and this is the only way to make it right, to save Dean, to save you--"

"Dad - "

"I have to make it right. This is for you, Sam, you and Dean and Mary and your girlfriend--it's for all of us."

A tear dripped down Sam's cheek, and a sob caught in his throat. This was what he had feared, all along. That he was the darkness. That he was the cause of all the pain his family had endured. He had allowed himself to believe that he could escape it - and Jess had died. He had allowed himself to believe that he was hunting evil, not its source - but his father knew better.

Every natural impulse screamed for Sam to bargain, to fight, to escape - to stay alive. But one thought overrode every other, quieting Sam, preparing himself for the sacrifice. Dean. If, by surrendering his life, he could save his brother's, if by letting his father kill him, he could finally leave his family in peace, then he was prepared. He was willing.

"There's no other way, Sam."

Sam's struggles stopped and he held his father's gaze. Pain, fear, understanding passed between them. "I know. There's no other way."

His father nodded, and reached for the knife, grasping it by the ornate ceremonial handle. He looked at it, noting how the blade glinted in the light. He had sharpened it meticulously, preparing for the sacrifice.

John's fingers trembled, his knuckles white. There was no turning back. He placed a steadying hand on Sam's head, gently leaning it back to expose the long lines of his throat.

His vision tunneled, focusing in on the soft, smooth skin. The blade glinted in the candlelight as he moved it closer. The serated edge wavered in his hand. John was so close to Sam he could feel his son's harsh breathing. Sam's breath caught in his throat, as the blade touched the exposed skin. For a moment, John thought Sam might speak, might cry, might make some move to stop him, but there was nothing.

With one last glance, he looked into Sam's eyes. At first he could see the dancing flames of the candles, but beyond that he saw the fire as it erupted over Sam's crib, and he saw the blood -- Mary's blood. Mary's eyes were pleading with him, asking for a reason, begging an answer.

He blinked and the image was gone, replaced by the deep pupils of his youngest son's eyes.

He had his answer.

His trembling gone, he pressed the knife solidly against Sam's neck, pulling it quickly and deeply across. Blood blossomed in its wake, seeping from the straight line and engulfing the blade.

A soft gasp escaped Sam's lips. John took the blade away, mesmerized as the blood spread rapidly, running down the length of Sam's neck and dampening his t-shirt.

John stepped back, letting the knife clatter to the ground. Sam's eyes shone with pain, but his mouth was set with determination. It would be over soon.

Sam felt the white-hot slice across his skin, and then the sudden flood of warmth as his blood began to flow. He was lightheaded, overwhelmed by the emotion and blood loss. He could feel lines of coldness trailing up from his fingertips and he shivered.

He had never thought much about his own death. Not that there hadn't been close calls along the way, but he had always been more concerned about the lives of those around him. Dean's. His father's. The innocents they saved. He had never tried to imagine what he would see or feel or think, whether it would be instant or drawn-out, pain-wracked or peaceful. He didn't think about it now, either. He focused on his father, garnering what little solace there was to be found from knowing that finally--finally he had been the good soldier his father had asked for. Finally, he had found the courage to comply with his father's command.

He hoped Dean would understand. Dad will take care of him. Dad will make it all right. Dean will be safe now. Those thoughts calmed him, and reinforced his resolve.

John was surprised by the sudden flow of tears down his face. He had not expected it to hurt so much. Sam looked so alone, so dejected, still tied to the chair, his head hanging toward his chest, his life force spilling, draining away, unchecked.

Compassion flooded him and he rushed to Sam, grabbing the knife to cut at the ropes that bound his son. His fingers felt numb now as they sliced, working at Sam's feet, Sam's hands, and finally his chest. Sam fell limply into his arms, and John caught him awkwardly, lowering himself to the ground, Sam in his lap.

He gazed into Sam's face. His features were already white, paling by the second. He seemed to relax in his father's grasp, the pain nearly vanishing from his face. John choked on a sob. "Sammy...I--it had to be."

Sam took an uncertain breath, rallying his fleeting strength. His mouth hovered open, haltingly formulating the words. "I . . . understand."

Blood covered Sam's throat, soaking his t-shirt, growing in a sickly puddle on the floor.

His voice was breathless. "As long . . . as I'm alive . . . there's no . . . peace."

John held Sam, cradling his baby, holding his knowing gaze.

The blood poured fast but Sam died slowly. How many times had he tried to stem the flow of Sam's blood, tried to keep that life force within his youngest child? But as the life from within Sam was released, so was his power, his destiny, his curse. Mary had been the first sacrifice, a token. Sam was the real thing, the last sacrifice. John let the blood cover him, cover Sam, atone for the sins they had all committed.

Sam's mouth was open, moving as if to speak, but his words bled out of him before they were formed. But John could see the message in his eyes--a message of forgiveness, love, regret.

The look lingered and John stared hard, unable to blink, until Sam's eyes slowly unfocused. His breathing ceased and his heart stilled, and the sacrifice was complete.