Castle came around chained to a wall in a dungeon. Well, okay, a basement, but it would be a dungeon when he told the story. He blinked groggily in the dim light, lifting his thudding head to look around. Everything was in shades of grey. The floor was rough concrete with dark unidentifiable stains creeping across it. There was a bench with blurry shapes on it against one brick wall. A tiny window was high up in the wall opposite Castle, showing the dull light of very early morning. The crick in his neck protested painfully as he turned his head to investigate the third wall. A flight of stairs waited in the corner, a torturously long way away. And speaking of torture – he tugged experimentally with one aching arm, but all that happened was the clank of chains and the bite of cold metal into his wrist. He kicked out with his foot, realising he was dangling above the floor, his whole weight on his arms, which now that he was waking up were starting to really hurt. His foot would only move a couple of inches. He wrenched down with his arm again, harder. Still nothing happened.

Castle was just starting to panic when a voice spoke from immediately to his left, and he realised that he was not just chained to a wall in a basement. He was chained to a wall in a basement with Dean Winchester, a delusional serial killer with a bounty on his head and some seriously scary people after him.

Dean had let him go when the other guy had turned up with his cronies. Castle had tried to escape, but it was dark and Dean had bashed in the wall and come up with the rock salt. He'd flung it all over the place, and it was slippery and hurt like a bitch when you got a handful in the eyes. But still, Castle had felt like he was doing a decent job of escaping, dodging blind punches and rolling out of the way of Dean and a bad guy smashing into the wall, locked in combat. He'd even dived out of the way of a flung knife, and he kind of wished Beckett had been there to see that. It was the armchair that got him. It hadn't landed on him, luckily, because it looked heavy enough to kill, but he'd seen it coming and dashed straight out of its path into the tackle of a guy that was going to be a lot bigger when he told the story. He'd come down hard, bashing his head on the wall and passing out.

"You okay, man?" Dean Winchester was asking.

Castle would have liked to come up with a witty and cutting remark to the effect that he obviously wasn't alright, being chained to a wall in a basement, but his brain wasn't working right. "No," he said.

Dean's chains rattled. Castle turned his head to look at his fellow prisoner, ignoring the shooting pain that ran through him. He could practically hear his shoulders creaking under the strain of holding his bodyweight off the floor. He had to crane his neck forward to see around his arm, but there Dean was. Dean's features weren't clear through the darkness and the fog of concussion, but he looked in fairly good shape, considering the circumstances.

"Grab the chains with your hands, it'll ease the strain on your wrists," Dean advised him.

Castle straightened his arms, wrapping his fingers around the thick chains that dangled above the manacles on his wrists. Huh. Dean was right. That was better. It didn't feel as much like all his joints were threatening to come apart. "Do this often?" he asked.

"You'd be surprised," Dean said dryly.

Castle was torn between morbid curiosity about what would cause someone to be chained up multiple times, and really not wanting to know.

Dean continued. "I am so sorry about this. I don't know why they took you too, but I will get us out of here, I promise."

Maybe it was the concussion talking, but Dean was really not seeming like such a bad guy right now. It seemed being chained up in a basement together could forge unusual friendships.

Footsteps sounded on the floor above. Castle's panic returned with vigour. He struggled against his chains with all his might, but they remained stubbornly anchored in the wall. "Who are they? What are they going to do to us?"

Dean evaded the question, tugging sharply and repeatedly at his own chains. "Did they leave you your phone? Wallet? Paper clip? Anything?"

Castle wriggled, feeling the pockets of his clothes flap against his body. The familiar weight of his phone was gone, and his wallet didn't slap against his leg, but his notebook remained in the inside pocket of his jacket, the spiral binding comfortingly familiar against him, pencil still safely tucked into it. "I've got a notebook," he offered.

"What kind of notebook?"

Castle described it. It was small and discreet, with a thin wire spiral binding it at the top and crisp white pages with blue lines, perfect for note-taking.

"Awesome," Dean said, and surprisingly, didn't sound sarcastic. The footsteps crossed the floor above them. They were heavier this time, almost like they were mocking him. "Which pocket?"

"Inside left."

"Okay, I'm not groping you; I'm going for the notebook. We can use the wire to unlock the chains."

"You've got a hand free?" Castle asked in surprise and annoyance. Why hadn't he mentioned the before?

"Well, no. I'll have to dislocate my thumb to get my hand out of the cuff." Dean said it casually. Castle shuddered. He knew it could be done. Derek Storm had done it regularly, and no-one could say Richard Castle didn't do his research. He'd even tried it himself, just to get the sensations genuine, but he'd pulled out long before he'd had any shot at actually slipping the cuffs. It was seriously painful, and anyway, a writer needed his hands.

Dean did it without so much as a squawk of pain, and soon his right arm was stretched out towards Castle, fingers groping for the pocket with the notebook. Castle did his best to swing his body closer, ignoring his aching limbs.

"Beckett will find us soon," he said, more to himself than Dean. He supposed the police was more of a reassurance to him than to someone who'd spent five years on the run from the cops anyway. "She's the best detective on the force, and she's definitely looking for me." He ignored the little voice in his head that reminded him he hadn't told anyone where he was going.

Dean didn't reply, concentrating on running his injured hand up Castle's side in search of the pocket that held the notebook. He'd just slipped his fingers into the pocket when the lights came on.

Castle blinked and turned his head against the sudden harsh white light. The pressure of Dean's fingers left his side as Dean pulled his hand away.

As Castle's eyes adjusted to the light, he made out a figure crossing the room from the stairwell. It was one of the three from the night before, the first that had spoken to Dean. He was average height, with a slight build, delicate features, mousy hair and eyebrows that disappeared in bright light. He looked unassuming, or he would have, were it not for the straight razor he carried closed in his hand and the crazy smile stretched unnaturally across his face.

Castle let out an involuntary squeak of fear, but the man ignored him, looking only at Dean. The crazy smile widened.

"Dean, Dean, Dean," the man said, his voice silky and quiet, "You have been a naughty boy, haven't you. Slipping your chains like that. That wasn't smart, Dean. You know what happens when you try to escape."

Dean looked worse in the light, his plaid shirt ripped and spotted with blood from a cut on his chest. A bruise discoloured the skin of his jaw, under a shadow of stubble, and there was a cut over his eye with a trail of dried blood running from it. He was glaring at the man with the razor.

"Oh, skip the speech and get on with it," he growled, suddenly sounding very dangerous.

"But the speech is the fun bit." The man flicked the razor open, running the pad of his thumb along the sharp edge. Drops of bright red blood rolled across the shiny surface of the blade. "I'll tell you what: I'll do the speech and the torture at the same time. How's that for efficiency?" He licked the blood off his thumb.

Castle did his best to shrink back into the wall, and saw Dean doing the same, trying to get as far away from the razor as possible, all the while glaring fiercely at the mousy-haired man.

The mousy man stepped toward Dean, razor at the ready. His eyes seemed to flash black as he rested the edge of the blade gently on Dean's abdomen. It was time for a little reckless bravery, just to buy time for Beckett to find them. "The police are on their way," Castle said. His heart thumped hard and fast in his chest as the man turned to look at him. He couldn't take his eyes off the razor, now pulled away from Dean's skin and moving towards him. "If you stop now they might be willing to make a deal, but if you cut someone with that you'll go down for a long time."

The man stepped away from Dean, towards Castle. The razor glinted as he raised it to Castle's face. Castle couldn't breathe, the sharp edge resting on his cheek, just barely touching him.

Dean's chains jangled. "Hey, over here! Let him go. You've got me, you don't need him, just let him go."

The razor moved lightly down Castle's cheek, removing a line of five O'clock shadow. Castle did his best to follow it with his eyes as it neared his throat. Then, thankfully, the razor was pulled away. "Well, no, Dean," he said, eyes fixed on Winchester, "I'm not going to let him go. We might need him for… leverage." Castle tensed. He really didn't want to know what that meant. "But you're right. I shouldn't be wasting my time on him when I have a celebrity to work with."

Castle couldn't help feeling a tinge of relief as the man stepped back towards Dean, and immediately felt horribly guilty for it. It wasn't that he wanted Dean to get hurt, but it was human nature to be relieved when the immediate threat of torture was removed.

Dean struck out with his free hand, landing a blow on the man's cheek. "Who are you?" he demanded.

The man's eyes narrowed and he grabbed Dean's arm, slamming the swollen hand against the wall and slapping the cuff back on. "You can call me Joe. Now, Dean, what are we going to do first?" He ripped open Dean's shirt at the front, sending buttons popping to the floor, and pressed the tip of the razor to the bare skin of the chained man's impressively muscular abdomen. "No angels to save you now, are there?"

Castle watched in horror as the razor drew a thin line of blood down Dean's belly. Dean barely flinched and didn't make a sound.

"What a superbly high pain threshold you have," Joe commented, "I'm going to have to put some effort into this." He made another shallow cut next to the first, and another beside it."

"Weren't you supposed to be introducing me to your boss?" Dean asked through gritted teeth.

"Oh, he's on his way," Joe said, "But we're allowed to have fun first." He dug the corner of the blade into one of the cuts and twisted. Dean screwed up his face, but still didn't make a noise. Castle could see his breath coming faster and his muscles trembling, though. It must hurt like hell. He wanted to make it stop, but couldn't really see how.

Hurry, Beckett. He sent out telepathic messages, and closed his eyes so he wouldn't have to watch.

"Where was I?" Joe asked in his velvet voice. "Oh, that's right, the speech. No one's coming for you, Dean. Sam doesn't need you anymore. He just can't wait you be free from your controlling, needy presence so he can say yes. Really, when you think about it, this is a good thing." He paused, doing something that caused Dean to let out low groan. "You know you can't win. You're exhausted. You can't save the world. You're pathetic. But now we've got you and you can finally die. You won't have to fight anymore. It'll be painful, of course…"

Dean groaned again. Castle tentatively opened an eye, and wished he hadn't. Blood covered Dean's torso, running down over his jeans on pooling on the floor beneath him. But then Dean started to speak in a surprisingly strong voice, so maybe it wasn't as bad as it looked. It sounded a lot like the exorcism Castle had found on the internet when he was researching Devil's Storm.

The man laughed. "Trying to exorcise me, Dean? You're going to have to do a lot better than that. Now, what should I do next? I know, I'll gouge one of those pretty green eyes out."

Footsteps sounded across the room. Castle opened his eyes again.

"Hey, man." It took Castle a second to realise he was being spoken to. "Are you okay?" Castle let out a hysterical giggle. The guy being tortured was asking him if he was all right. He nodded.

"Okay good. I'll distract him; you slip your chains and get away. Find my brother Sam. Yell 'Christo' at anyone upstairs."

"I'm not leaving you here!" Castle protested. "Look, Beckett will be here soon, I promise."

Across the room, Joe was doing something at the bench with a blowtorch.

"Dude, cut the 'my Westley will come for me' crap. Even if she did make it in time, your girlfriend won't be able to help. She doesn't know how to deal with demons. We have to save ourselves, and that means you have to escape and leave me here."

Demons? Now that Dean mentioned it, it kind of made sense, especially with the black eyes and all the talk of world saving. Crap. This was one time when Castle would have been really, really glad to have his theories debunked, and it turned out it was even worse than he'd suggested.

Joe was coming back, holding a spoon with a glowing red bowl. Castle shut his eyes and worked at dislocating his thumb. Dean was swearing violently and thrashing in his chains. Castle tried not to listen. He concentrated on his thumb, and tried very hard not to think about the man next to him having his eyes gouged out with a spoon.

It took him longer than he'd have liked, but finally his thumb popped out and he twisted his hand through the metal loop, slicked with blood from his struggles. His chains clanked and his joints creaked as his other arm took all of his weight. He reached into his pocket to pull out the notebook, untwisting the wire. It was surprisingly difficult without the use of his thumb, but finally he got it straight enough to use. As he was lifting it to the cuff around his wrist, Dean began to scream in earnest. The cuff took him a long time. Even with lock-picks, he wasn't all that good at picking locks. When he had only a thin piece of wire and couldn't see what he was doing, he was much worse, especially with only four fingers.

When the cuff came undone, Castle tumbled forward, landing heavily on his injured hand. He let out an involuntary yelp of pain and glanced up at the torturer to see if he'd heard. He hadn't. He had a blowtorch now. Dean's screams were getting weaker.

Castle worked at the manacles on his ankle. He freed his right foot, then his left.

Dean stopped screaming. Joe swore, setting the blowtorch down and marching straight past Castle and up the stairs.

Castle looked at Dean Winchester and vomited violently on the concrete floor. He gathered his courage, forcing himself to stand up, pausing for a moment as his legs threatened to buckle beneath him, and making his way over to Dean. He placed his fingers on the bloody throat. No pulse.

Castle took a deep breath and looked around the room. He forced his trembling body to cross the room to the bench and drag it, shove it, and otherwise force it across the room so it was under the window. He stood unsteadily on it, reaching up to smash the glass with a slightly bloodstained hammer. He tossed his jacket up to protect himself from broken glass, and examined the contents of the bench for something to pull himself up on. He tied a meat hook onto a heavy leather whip and cast the end up like an anchor. It took four tries, but it caught in the earth outside. He tugged at it to make sure it would hold, and then used it to help heave his exhausted body, panting and shaking, up through the window. He was running mostly on adrenalin, nearly collapsing in a heap after squeezing out through the window, but knowing he had to get away. Get home to his daughter and mother and friends, and find Sam Winchester to save his brother's body.

He began to crawl along the dirt strip between the house where he'd been imprisoned and the one next door, going towards the street and people. The bare soil was hard, digging into his grazed hands.

There was a violent smashing from inside the house, followed by shouting and gunfire. The police had arrived.