Sam always kept their journal. Not right from the get go; he started it after they took down the Hook Man in Toldeo and backdated the rest. And not like Dad's, with long handwritten paragraphs about the hunt and bits about their lives all mixed together: His was an excel spreadsheet, neatly listing places, dates, names (victims and monsters), bullet points for what happened and how they'd stopped it, and here and there notes as they learned new stuff from the lore. But mostly, names: Names of people involved, the ones that had information, the ones that were targeted, the ones they saved, and the ones they didn't.
Printed out, it covered two walls.
Dean kept two lists, both in his head; shorter, just names. One was everyone he'd ever failed to save: Charlie. Kevin. Bobby. Jo and Ellen. Ash. Dad. Adam. Jessica. So many others. And every time he thought of any of them, he saw their deaths: Eyes burned out. Explosion and hellhounds. Bleating hospital monitors. Fire and smouldering ashes. Blood spattered bathtub.
Every time he thought of any of them, his heart was shredded again.
The other list named every son of a bitch he'd have to kill to save them.
"What you're proposing... Dean," said Cas. "Dean, this could go very badly."
Dean leaned back in his chair slowly, feeling the ache in his eyes from too many hours dry sobbing in the shower and too bone-tired from fighting to care. "Compared to what, exactly?" he said. "They're already dead. They're all already dead, and it's on me."
Shaking his head, Cas pulled out the other seat with sharp and jerky movements and sat down. "If I take you back in time, the moment we change anything, this future will cease to exist. Everything that has happened since that moment will be erased."
"Sounds good to me. Let's McFly this fucked up timeline."
"You don't understand," he said intensely. "If we mess up anything, anything at all, all the good we've accomplished will be gone as well. The people we've saved could die, or worse: The Apocalypse could come about after all. The world could end."
"As far as I'm concerned, it already did."
Dean hesitated, looked down. Cas was on his list too, in the 'screwed over too many times' part. "Look, man... I know I've got no right to ask you any favours. What I did to you– what I almost did. That can't be forgiven."
"That was the Mark."
"It was me."
"Well, I blame the Mark, and it's gone now," Cas said. "We all paid the price for that, Dean, and it was too high. The question is, what will you do next time Abaddon threatens your family? Or Lucifer, or Eve, or any of the others? I can't watch this happen again, not ever."
The price. Cold terror slid up Dean's gut, squeezing his heart until he almost puked. "The Colt will kill her," he replied, fighting it down, "as long as we don't lose it this time. It'll work on all of them, except Lucifer, and we can keep him trapped in the cage. If we kill Lilith before the other seals break, he'll never get out. No Apocalypse. Michael will be furious but hey, douchebag." He tried to smile. It didn't really work.
Cas rubbed his eyes and let his shoulders slump the way he always did when he was giving up, giving in. "You're playing a very dangerous game, Dean," he sighed.
"It's all I've got left."
All either of them had left, now. Cas nodded. "All right," he said slowly. "I'll do it. For you."
Something that might have been hope sparked in Dean's chest, jittery and sloshing like his stomach after drinking too much booze. His throat got tight and he clenched the armrests until he could talk without shaking. "Right, okay," he said, climbing to his feet. "Come here."
He stepped over to where Sam's records were taped to the walls. "These," he said, "are all the people we're going to save."
There were hundreds of names there, and thousands more that weren't; people lost to monsters before he and Sam caught the case, or to the Croatoan virus or demon deals or Leviathans or whatever. So many people.
To his credit, Cas just shrugged. "We're going to need a plan," he said, reading over the lines, "some sort of strategy. Every change we make in the past is going to have a ripple effect. We'll have to be careful."
"Then grab a beer, buddy. We've got work to do."