It was a long shot, they knew.

The Mark had taken over, and the brother Sam knew and loved had all but vanished behind a mask of stone, consumed with a lust for the kill, and not even Sam's tears, Sam's desperate, begging words, could sway him from his path.

Sam found himself closing his eyes, whispering a prayer to whoever was still listening, as Cas's low voice chanted quiet Enochian words over the item Sam held in his hand. Sam's eyes stung with tears, and he blinked them away as he looked anxiously at the angel, who looked back at him, solemn and apprehensive.

"If this doesn't work..." He didn't have to finish.

They were out of options.

Nothing could stop Dean anymore. No opponent could stand against him in battle. No spell could hold him - at least, not for long.

"Get out of my way!" he snarled as Cas stepped in front of him.

Cas didn't respond, just touched Dean's shoulder and and spoke a few words of Enochian. Dean glared and moved as if to step forward - but found himself abruptly frozen to the spot where he stood. His eyes narrowed with menace as he ground out with an effort.

"When I get out of this... and I will get out of it... you're next, angel."

Cas just gave him a long, sad look as he stepped back, out of Sam's way. Sam stood facing his brother, tears streaking his face, as he reached into his pocket for the item Cas had blessed earlier - infusing it with every ounce of power the love and memories associated with it held.

"You're making a mistake, Sam," Dean said, cold and threatening, his speech already free and easy again; the spell was wearing off. "I'll cut you down as easy as anyone else. We're not brothers anymore, remember?" he sneered.

"I know you will." Sam's voice was soft and sad as he ran the simple strand of leather through his fingers, holding it up in both hands in front of Dean. "But... you're wrong. I was... wrong."

Dean's eyes widened as he saw what Sam held in his hands. He flinched slightly, still unable to pull away, as Sam lifted the cord and fastened it gently at the back of Dean's neck, the icon attached to it hanging against Dean's chest. Dean stared down at it, confusion breaking through the violent fury in his eyes - as if staring at the face of someone he knew, but couldn't quite place their name.

Sam reached out a tentative, trembling hand to touch Dean's shoulder, tears streaking his face as he choked out, "We are still brothers. And... if you cut me down..." Sam shook his head, a sad smile on his lips, love shining from his eyes. "... I'll still love you. With my last breath."

Dean looked up at him, green eyes wide and stricken. "S-Sammy?" he whispered, sounding suddenly lost, and so very young.

"Yes," Sam replied, relief flooding through him. "I'm right here, Dean."

"Sammy," Dean choked out a sob, stumbling forward into Sam, who immediately put his arms around him, supporting him, falling with him as Dean dropped to his knees.

"It's okay," Sam whispered. "It's okay, Dean... I've got you." His throat ached, his tears falling into his brother's hair as Dean's soaked the shoulder of his shirt. "I'm right here... and I'm not going anywhere."