This story occurred because for reasons outside of my understanding when I watched 'Stairway to Heaven,' the second last episode of Supernatural, I thought I was watching the last one. Cue my extreme confusion. Watch the ending of 'Stairway to Heaven' and imagine you are watching the finale. It is quite obviously not a finale! But I was confused, hence the confusion.

(I actually read a review of Supernatural, whilst sitting in on a friend's fascinating uni lecture on property appropriation or something, that actually literally said that 'Stairway to Heaven' would've made more sense as a finale the 'Do You Believe In Miracles.' I can attest that this is NOT TRUE.)

Anyway, so in the weird 24 hours the ensued I wondered what would happen after the 'finale,' and something along these lines was what I thought of. I have an idea of what would happen next but we'll have to see if I ever get around to writing it.

For now, this is how I envisioned the immediate aftermath of 'Stairway to Heaven.'

Enjoy.

Sam and Cain.

Sam didn't see it coming.

When Gadreel had entered the main chamber of the Men of Letters bunker and asked for a chance to fight with them Dean had looked across at Sam. Sam had looked back without really seeing. He'd raised his eyebrows to say "Why not?" with his expression but he'd been thinking about what Dean had said a few moments ago and was still feeling it cutting him up inside. Sam had been worrying about the changes he'd seen in Dean so much that he failed to see the signs of more.

So when Dean drew the First Blade across Gadreel's chest in one short, brutal swing Sam felt like he'd been electrified. Dean had never caught him off guard like this before, never. As he leapt to Dean's side and seized his brother's arm Sam knew something was irrevocably fractured between them.

Light and blood streamed from his chest as Gadreel staggered back. He fetched up hard against a blue-stone pillar, a remnant of prestige long since lost, and one hand lifted drunkenly towards the wound. Teeth bared around a feral noise Dean lunged again but this time Sam and Castiel stopped him. Sam clamped his hands around Dean's arm and braced his feet on the ground but even with Cass restraining Dean from the other side it was hard to hold him. Slippery and strong Dean snarled and fought to get to the injured angel as he slid to the stone floor. The air reeked of sweat and blood and ozone.

Surrounded by the computer banks and all of the Men of Letters delicate instruments Dean looked by comparison savage and bestial. The noises he was making were just like those of the monsters the bunker and all of its technology had been created to destroy. There was something so far from anything remotely human in Dean's face that Sam felt a stab of sickness, dread, deep in his gut.

The struggle stopped slowly, and not because of Sam or Cass's efforts. Dean was wrestling against them, then leaning, then simply seemed to disregard the fact that Cass and Sam were there entirely.

He just stood there, eyes fixed on Gadreel.

Growling.

"Dean!" Sam shouted. By now he had a handful of Dean's blue jacket and he shook it. He wasn't gentle.

Dean did not seem to even hear him. He kept making mindless guttural noises with each exhalation like he was panting with hate.

"Dean," Cass said from the other side, with as much success as Sam.

Sam saw Cass's eyes flick down to Dean's hand. There were specks of blood on his skin and Dean was holding the ugly jawbone so tightly his fist was trembling.

"Dean, let go," Sam shook his shoulder again and finally Dean looked around. His gaze fell on Sam's hand then slowly crawled, as a heavy thing, up to rest on his brother's face.

Dean's eyes were not familiar.

"Let it-"

"He's working for Metatron," Dean interjected, ignoring Sam beginning to speak.

"I don't think he is, Dean," Sam's eyes flicked from Dean to Gadreel, who was slumped over and blatantly incapable of such energy demanding things as backstabbing and consciousness.

"He's working for Metatron!" Dean yelled. He jerked the Blade up to gesture at Gadreel, badly jostling Cass who hung on with a grim expression.

"Gadreel said he could give us Metatron," Cass reminded Dean when his arm had stilled again.

At the sound of Cass's low voice Dean's head snapped around to face the angel's and his body went tense and still, like a hunting dog hearing a rustle in the undergrowth.

Sam was suddenly very, very uneasy.

"He thought about what you said?" Dean asked quietly.

"Cass," Sam said.

"Shut up," Dean snapped at Sam and suddenly wrenched himself sideward from his brother's grasp.

As Dean stepped towards him Cass immediately let go and retreated, his eyes on the First Blade.

"Why is it that everything with you is so completely screwed up?" Dean demanded.

Cass's hands were up, both wary and placating.

"I…" Cass started hesitantly but Dean wasn't finished.

"Even when you actually manage to do something right it's so mixed up with wrong it causes us problems."

"Dean," Sam admonished.

Cass looked wounded. Beneath the silver florescent lights on the walls and above the yellow glow of the war table he looked exposed and vulnerable.

"You've been talking to Gadreel, the angel who killed Kevin, without telling us?"

Now Dean gestured at Cass with the bloody Blade. Sam did not want to provoke Dean by trying to intercept him but the fact that there was nothing between Cass and the First Blade but Dean's instability was sending adrenaline jolting through his body.

"I wanted information on Metatron," Cass explained, sounding like he was being very careful to sound calm and speak clearly. "I met with Gadreel to ask if he would give it to me."

"But you didn't tell us," Dean insisted angrily.

"There was a lot happen-"

"We shouldn't have to ask, Cass!" Stepping forward again Dean raised the Blade and, seemingly compelled out of reflex, Cass also took a step closer. His hands were still up in a futile soothing gesture and he looked anguished; the hurt of Dean's disbelief had made him forget about the influence of the Mark of Cain.

"Cass!" Sam said sharply and leapt between them. He chose Cass to push backwards, possibly realizing unconsciously in the millisecond that he had to choose that with the Mark of Cain Dean was beyond his capability to move or stop on his own.

However this meant that for a second Sam had his back to his brother.

And that frightened him.

For a moment Dean was in Sam's blind spot and despite all of the times his older brother had saved him and despite everything they'd been through, fear of a threat he couldn't see spasmed through him.

He whirled around to face Dean again and the moment was over, but Sam's heart was still thumping hard in his chest. Looking at Dean and the Blade in his hand Sam felt an inexplicable but complete certainly that he would never forget how it felt like to be afraid of his brother and afraid of what his brother might do.

"Dean," Sam said, his voice quavering slightly before he could control it, "drop the blade."

Dean was glaring at Cass over Sam's shoulder. He was shaking again and the noise of his ragged breath echoed off the tall walls like a thousand monsters breathing.

"Angels…always angels…" Dean growled in disgust and straightened. As he did so he lowered the blade and Sam had to stop himself from letting out a wobbly sigh of relief.

"They're all either backstabbers," without taking his eyes off Cass Dean cocked his head in Gadreel's direction, "or useless," his head snapped back at Cass.

Behind Sam the angel shifted, the trench coat sliding over itself with the quiet shuck of material on material, but he did otherwise react.

"Drop the blade," Sam repeated. This time his voice was steady.

It had worked before. When Dean had lost control with Magnus and Abaddon Sam had been able to call him back, back from wherever he had disappeared to. Their brotherly bond had overcome the power of the Mark, or something.

Now, finally seeming to hear what Sam was saying for the first time, Dean looked down at the Blade. He tipped it in his hand and a line of blood dripped from one of the ancient incisors forming its jagged tip. The odd, longing expression on Dean's face reminded Sam strikingly of himself drawing a thumb down the demon-knife, craving blood like a junkie.

Dean looked up from the blade. His expression was uncompromising.

"No."

Sam shifted his feet.

"Dean-"

"I said no, Sam," and Dean bent his elbow, holding the Blade close to his body in a position poised to strike.

Sam narrowed his eyes and pressed his lips together. He forced himself to stand quiet and calm even as he felt everything slipping out of his fingers and spinning out of control.

"We need to go after Metatron, and we need itto kill him," Dean said as though this were obvious.

"Not now, not yet. Just…put the Blade down and we can talk to Gadreel and find Metatron," Sam reasoned, but he could feel it was hopeless.

He didn't want to give yp.

When Dean did nothing Sam ever so slowly reached out.

Seeing Sam raise his hand Dean's expression twisted and he lifted the Blade, either threatened or threatening.

Sam froze.

"No more Gadreel, no more Cass," Dean yelled at Sam. "Enough angels! We're doing this on our own."

"What?" Cass exclaimed.

"We can't hunt angels with angels, they're all traitors," Dean spat, wild and beyond reason, the Mark of Cain glowing feverishly. "Gadreel will betray us and Cass will screw it up. We'll hunt Metatron on our own Sam, like we've always hunted before."

Sam stared at Dean in shock.

"That doesn't make any sense. We need the angels to find-"

"No we don't," Dean stepped forward and seized Sam's raised hand by the wrist. His grip was so tight Sam felt Dean's knuckles grinding against the bones of his wrist. Taken by surprise he was yanked off balance as Dean threw him away from Cass.

"Sam!" Cass yelled.

Catching his balance again Sam's head whipped up. The First Blade was outstretched, a few hand widths from Cass and holding him back. Sam could see the Mark of Cain on Dean's raised arm. It was a bright, demonic red and his eyes hurt to look at.

"You can stay with him," Dean snarled to Cass, jerking his head towards Gadreel. "You'll have all the time in the world to talk to him when we're gone."

Cass's eyes were wide with alarm and by his expression he was at an utter loss as to what to do.

"Dean, we shouldn't leave the-" Sam stepped forward.

It was a mistake.

Pivoting on his toes Dean backhanded Sam across the face. It felt vaguely similar to being bashed over the head with a sledgehammer. Sam crashed to the floor, left cheek numb and ears ringing with a spiraling whine. Dean had hit him with the hand holding the blade and when Sam reached a dazed hand up to his face he felt a wet smear of angel blood beneath his watering eye.

Through the wavering drone in his ears and the cotton that had suddenly surrounded his brain Sam heard Cass yell Dean's name. Dean had laid the First Blade lightly on Cass's chest. Though the Blade had not even creased the shirt Cass retreated a step. Pressing his advantage Dean followed, the teeth of the Blade leaving a bloodied imprint on Cass.

"Dean," Sam blinked hard and staggered to his feet. He had to throw his right foot out to catch his balance. "Dean, leave Cass alone."

Dean slowly stepped back with obvious reluctance and glanced at Sam.

"You're right," he said, inexplicably changing his tone, "he's not worth it."

Sam didn't understand what was going on. He didn't understand the way in which this new Dean thought. He seemed irrational, unreasonable, yet evidently to himself he made sense.

Turning away from Cass Dean moved to Sam's side. Sam couldn't help but flinch, even though Dean just put his hand on his shoulder to steady him.

"Let's go get the Impala," Dean said. The comfortable tone he spoke with grated over Sam's senses because the situation was so unutterably wrong.

But he agreed anyway. Because he had to. Because Dean was on a knife edge and there was no other choice.

"Okay."

"Sam," Cass said very, very quietly.

"Shut up!" Dean snarled aggressively, but Sam put a hand on Dean's shoulder in the hope that it would pacify him. For some reason it did.

"It's okay, Cass," Sam said.

Cass's expression showed that he found this situation the furthest thing from okay.

Dean wasn't rational and he was a danger to them both, but he still seemed to recognize at least on some subconscious level a twisted version of brotherhood. Though he had been hit Sam feared that if they pressed Dean Cass would fare much, much worse.

No, it was better to go along with Dean for now. The Mark was in full effect, still glowing an unwavering, brilliant red. It made more sense to appease this wild and dangerous Dean with acquiescence and wait until he had calmed down to try and reason with him and make him see sense.

Cass looked pained but he seemed to have read Sam's plan on his face and so said nothing else.

"Let's go," Dean commanded. He gave Cass one last look of contempt and, without even awarding Gadreel as much, turned for the door.

"Okay," Sam said again. The side of his face was losing its numbness and beginning to sting as he took one last look at the unconscious Gadreel and the lone and desperate Cass he was leaving behind. Then, as Dean looked over his shoulder to follow Sam's progress with a hunter's eyes, Sam turned and followed his brother.