Sam Winchester had a lead. He finally had a lead on a cure for the Mark of Cain. It wasn't much of a lead, but it was all he had. But he couldn't tell Dean. He couldn't tell Cas. They'd never let him do it. He needed to save his brother, though. And he'd succeed. It didn't matter the cost. He had to save Dean.
It was a long drive to the church. Sneaking out of the bunker had been a serious challenge, but he'd done it. He hit the road on Dorothy's bike and didn't look back. He knew what he had to do. Dean would never forgive him, but he couldn't just let his brother die.
He stopped at a crossroads just outside the road that led to the church. Getting off the bike, he took a deep breath. He opened his bag and retrieved a box. Quickly, he buried it and anxiously wrapped his fingers around Ruby's knife. If felt dirty doing this, but he'd do what he had to do.
"Sam Winchester," came a voice from behind him, "No devil's trap? I'm shocked."
Sam tuned around to see a beautiful woman with bright red eyes. "Do you know me?" he asked.
"I know of you," the demon said, "But who hasn't heard of the Winchesters?"
Sam stepped closer and asked, "Have you heard anything about me specifically?"
"Just that you're dangerous and a very problematic hunter," she said, "But I'm starting to gather that you like to waste time. Is there something you summoned me for? Sell your soul for something juicy?"
Sam grabbed the demon's wrist and snapped demonic handcuffs on her. "I just need you," he said. She looked from Sam to the handcuffs with fear in her eyes.
As they drove up to the church, the demon gasped. "Is this...?" she asked.
Sam didn't respond. He could see the collapsed part of the roof where Lucifer had blasted out of the cage. He knew this church very well. He didn't need to answer the demon. She knew this church as well as any demon who'd been around for the apocalypse that never happened. This church held the door to Lucifer's cage.
Sam stopped the bike and pulled the crossroads demon with him. She protested loudly, but Sam paid no mind. This was the only way to save Dean.
Once inside, Sam dragged the demon down the hall where the doors hung ajar from that concussive force all those years ago. A dark crater filled the center of the room from where Lilith's blood had opened the cage. He was surprised not to see Lilith's or Ruby's corpses lying strewn about the floor. They must've been vaporized by Lucifer's grace.
"We can't be here. The king wouldn't want--" the demon started.
Sam cut her off, "I don't care what Crowley wants. It's his fault that I have to do this." He pushed the demon against the cracked altar. He raised Ruby's knife to the demon's neck.
The red-eyed woman stared at Sam with wide eyes.
"I'm sorry about this," Sam said.
He made a deep slice in the demon's neck and pressed his lips to the soft flesh and flowing blood, drinking as much demon blood as he could get.
The crossroads demon screamed.
Drinking the blood felt horrible. It felt like reopening old wounds that the trials had closed. It almost made Sam stop drinking. But it also felt good in a way. It felt good to feel that strong again, and it felt good to go back to something he knew. And he needed to do this for Dean.
But the demon blood wasn't enough. Not for what he wanted to do anyway. Sam stopped drinking just before the demon passed out. She blinked at Sam, clearly dazed from the loss of blood and energy.
Sam still needed to sacrifice an innocent. He aimed an outstretched hand at the demon, stretching a muscle he hadn't used for a long time. Slowly, he ripped the demon from her host, watched as the black smoke dissolved into the ground.
The human in front of him gasped and coughed, looking at Sam through tired, pained eyes.
"I'm so sorry," Sam said.
He lifted the weak woman onto the altar, and with one quick, calculated motion, slit her throat.
The blood slid down the altar, draining her life with it.
Sam knelt on the ground before the altar. Metatron said that the Mark of Cain was magic from the days of God and Lucifer. He'd said they couldn't talk to Lucifer. Honestly, that just wasn't quite true.
There had been plenty of times in the cage that Lucifer had taunted Sam with the knowledge of what Azazel had done to set this whole plan in motion, how many people had died just for Sam to fail.
He was afraid to be near Lucifer again. He was afraid to be near the cage again. But he needed to do this. He needed to be brave for Dean.
And now, Sam knelt before the mouth of Lucifer's cage, and using his demon blood fueled power, whispered through the door.
"I have come to make a deal," Sam said.
The corpse of the woman shook violently, and her mouth opened, releasing the voice of Lucifer himself. The archangel said, "My, my isn't this a surprise. What deal could Sam Winchester want to make with the Devil he caged?"
"I need to know how to remove the Mark of Cain," Sam said.
"The Mark?" Lucifer asked, "What mess have we stumbled into this time, Sam?"
Sam said, "Just tell me how to remove it."
"Release me," Lucifer said.
Sam stared at the woman on the altar. He couldn't let Lucifer out. He couldn't do that. He looked at his hands and said, "I can't."
"Then, you can't remove the Mark. I made it. I am the only one who can undo it," Lucifer said.
"You're lying," Sam said quickly. There had to be a way. There was always a way.
Lucifer said, "I told you I would never lie to you."
"Lilith is already dead, and I only have three of the Horsemen's rings. I can't open the cage," Sam said quietly.
Lucifer laughed. His dark laugh echoed through the shadowy walls of the abandoned church. "You must be desperate to be considering letting me out," he said, "There is another way to open my prison. If the life of my true vessel is sacrificed over the door, it will open."
Sam didn't think about it much. He'd done the self-sacrifice play before. He'd been considering releasing Lucifer ever since Metatron had said the archangel's name. It was the only option he had.
"How do I know I can trust you?" Sam asked.
Lucifer replied, "What choice do you have?"
Sam deliberated for a short moment before saying, "You have to remove the Mark from Dean, but you can't hurt him. The Mark is killing him, but I'd rather he die by the Mark than by you."
Lucifer said, "You've got yourself a deal, Sam. Let me out, and I'll cure Dean. He'll be good as new, and I won't touch a single hair on his head. You have my word."
Sam didn't like this one bit, but Dean was getting worse by the day. He needed to do something. At least with the Mark gone, Dean and Cas could deal with the Devil together.
"Okay," Sam said.
Sam Winchester stood up and faced away from the altar exactly where Lilith had stood so long ago. He took Ruby's knife in his hands and stared down the dark, empty hall of the church.
Crowley appeared in the hallway, staring wide eyed at Sam. "Sam, don't!" he shouted.
Sam raised a hand, and forced the doors closed with his will alone. Before the King of Hell could do anything to stop him, Sam stabbed Ruby's knife into his neck, ripping forwards before he lost consciousness.
The last thing Sam saw was the quickly approaching cement floor as he collapsed.
A soft yet strong voice reached Sam's ears. Death stood next to Sam with a hand on his shoulder. "Sam," the Horseman said, "What have you done?"
Before Sam could reply, a bright light with a shrill, shrieking sound filled his head. He was ripped away from Death and filled with the painful, blinding feeling of being strapped to a speeding comet.
Dean awoke from yet another nightmare to see Sam standing in his room.
"Sam," Dean said groggily, "What're you--"
Sam crossed the room and grabbed Dean's right arm. The Mark of Cain shone bright and seared against Dean's arm with a hot pain.
Dean cried out, trying to yank his arm from his brother. Soon, the sensation died down. The Mark was gone.
"Sam, how'd you do that?" Dean asked, bewildered. He stared at his arm in confusion.
Sam looked at Dean fiercely. "I told you," he said, "We will always end up here."