"You touch him again and I'll kill you I swear to God," Dean was barely conscious himself, but that didn't stop the blind rage that pounded through his skull and roared in his ears. Many times before, he'd seen Sam hurt; too many times for him to count, really, but not like this. Never had he been forced to watch as his brother was beaten within an inch of his life. Dean had taken a fair few hits himself, but only so they could shut him up. He gripped the arms of the wooden chair he was tied to so tightly that the skin of his knuckles broke, oozing blood across his hands to mingle with the rest. He tore his gaze away from his brother's broken body only once, to look around the room for any signs of escape; any signs of help. Then he returned his eyes as a foot connected solidly with Sam's ribs, a fist with his nose. Dean flinched, as though the blows had hit him as well as Sam. He didn't know how, but somehow Sammy had managed to stay conscious. Dean supposed he should be happy for that, it meant his brother was still alive. But as the kid's brown, pleading eyes turned up towards him, Dean wished they were both dead. Anything was better than this, wasn't it?
"Dean!" At the sound of his name, Dean looked around wildly.
"Dad?" He'd know the voice anywhere. But how could it be his dad? Dean couldn't see him, and John didn't know where they'd gone. Dean knew he should've told him, but Sam had been missing for almost four hours, and Dean hadn't known when John was supposed to be back.
"Dean!" The yell was closer this time, clearer.
Dean felt a sharp pain across his cheek and closed his eyes tightly. When he opened them again, he was looking straight at his father. It occurred to him that his dad had slapped him.
"Oh thank God," Was it just Dean, or did his dad look genuinely scared? "Dean, are you alright?"
Dean looked down at himself. There was no evidence of the apparent abuse he'd received, but he felt shaky, almost feverish. John cut the ropes around his wrists, and Dean gasped. It was like the contrast had been turned up, the world sharpened.
"Hallucinogen in the ropes," John explained quickly, helping Dean to stand, "We have to get out of here."
"Dad, wait…" It took a terrifying amount of effort to talk, and Dean's voice sounded raspy, "We have to get Sammy."
John stopped dead in his tracks, "Sam's here?"
Dean nodded slowly. He could feel his strength coming back, but he still felt like his head was stuffed with cotton wool. He'd probably only been in that chair an hour or two.
"Can you walk?" John asked urgently.
"Yeah," His voice was shaky, but they had to find Sam.
John took off and Dean followed behind, slower and unsteady, but determined. He took in his surroundings as they ran. It looked like they were in an old abandoned house. Everything seemed to be made of wood, and the floorboards groaned under their weight. The two Winchesters checked all of the downstairs rooms to no avail, but had better luck upstairs. If you could call it luck. In one of the bedrooms, Sam was tied, wrists above him, to the bed. Even from the doorway Dean could see the black that seemed to be spreading through the veins of Sam's forearms, delivering hallucinations to his mind. Dean looked down at his own arms, and saw the faint trails of the same black substance. But he'd only been there an hour or so, it had to be over six hours for Sam now. The kid looked worse than Dean felt. He was pale and shivering, covered in a thin sheen of sweat. All in all, he looked like crap. As soon as John had cut the ropes around Sam's wrists, Dean was shaking him gently, saying his name. It took a minute or so, but Sam's eyes opened and he blinked groggily. He was definitely alive.
"Dean?" He mumbled.
"Yeah, yeah I'm here Sammy," Was the relieved reply that Dean managed to choke out.
"Dude you look like crap," Sam was one to talk, still shivering, half slumped again his brother, eyes half closed.
"Yeah, right back atcha," Dean said, shaking his head. "C'mon, we gotta go." It was clear Sam wasn't going to be able to walk by himself, and Dean was barely keeping upright as it was. John was there though, stooping to pull Sam's arm over his shoulder.
"The Impala's just outside," He said, "We gotta go before the thing that got you two gets back." There was a weird light in John's eyes, and Dean knew that whatever had done this wasn't going to see another day. Anything that screwed with the Winchesters didn't live for very long.

It took them several minutes to get to the car. Dean pulled open the back door and John crouched, allowing Sam to practically fall off his shoulder and into the backseat. The youngest Winchester managed to pull himself enough in that his legs weren't hanging out the door. Dean pushed the door shut and got in the passenger side, John driving. It took them half an hour to get back to the motel, but that was enough time for both Sam and Dean to feel distinctly car sick. It was one of the few times Dean was happy to get out of the Impala. With minimal problems, Dean and John manoeuvred Sam into the motel room between them, and set him down gently on one of the beds.
"Get some rest," John said to Dean, "When you feel better, make sure you both eat something." Without another word he turned back towards the door. Dean didn't ask where he was going. He already knew.

When John returned a few hours later, Sam was still asleep. Dean had slept and eaten, then made sure that Sam wasn't gonna die of a fever before watching T.V. John didn't say anything when he came in, but Dean knew from the look on his face that the thing, whatever it was, was dead.

They left town the next day. But the images that Dean had of his brother's blood seeping into the floorboards never left him.