The house was dark and cold. It gave off a stench, the kind you only find in abandoned places where everything's been left to rot. There was a silence that seemed to penetrate the very walls and clawed its way inside you and made your breath catch. There was no hall after the front door; it opened straight into a living room. What was left of a couch lay tattered and sunken in the middle of the room and a door lay to the left, slightly ajar.

This was supposed to just be a normal hunt. It was just an angry spirit who'd been killing people. This time they thought it was on old WW1 soldier, seeing as all his victims had the symptoms of mustard gas poisoning. Only Sam had this terrible feeling that something was very wrong.

"Dean," he whispered, breaking the silence like a bullwhip despite his low tones.

"What?" Dean hissed back, salt gun raised towards the open door.

"I don't like this Dean," Sam warned.

"Well if you're scared why don't you wait in the car till I can check for the bogey man?" he mocked.

"Shut up Dean," Sam half snapped, half sighed at his older brother.

Something rattled beyond the door. Suddenly both brothers were poised, like true predators all their senses keened on their prey in the next room. Dean motioned to Sam to stay close and cover his back. Then, they moved slowly towards the door, automatically knowing exactly how to place their feet so that they made no noise on the dusty floorboards.

When they reached the door, there was pause as Dean laid his hand on the handle and looked over his shoulder for confirmation that Sam was ready. Sam tightened his grip on his gun, took a deep breath and nodded.

Dean flung open the door and both barrels were pointed straight down a short corridor. It was even darker in here than it was in the previous room. Dean switched on his flashlight and held it in line with the gun.

There was nothing but dust, and another door. Right at the end the door stood slightly ajar, just as the first one had. Alarm bells started ringing in Sam's head.

"Dean," he warned again, "I don't like where this is going."

"This is a little weird," Dean admitted, "But we still have to kill the son of a bitch. Weird is kind of what we do."

Sam wasn't convinced but Dean was already moving down the corridor and he wasn't about to leave him. He followed, far more cautiously this time; his senses on such high alert that he thought his heart would explode from the adrenaline.

At the end of the corridor, Dean slowly pushed open the door. There was another room, similar to the first, but this one had a table covered in a dust sheet rather than a sofa. They moved in, scouting out every inch of the room with their flashlights. There was nothing.

"I don't get it," Dean had stopped whispering, "This dude's been vicious so far, surely we should have seen something by now."

But Sam wasn't paying attention. His heart was in his mouth as he stood by the window, staring at the one thing he wished he would never see again.

"Dean," he called, his voice filled with tension.

"What?" responded his older brother, "What have you got?"

Sam took a pinch and held his hand up to Dean, letting it slowly trickle out from his fingers.

"Sulphur," Dean gasped.

"That table," Sam gestured with his head, "Doesn't that sheet look a bit new to you?"

Dean looked at the table then back at Sam, his eyes worried. They both went over and, after grabbing a corner each, wrenched the dustsheet off and let it fall to the floor.

On the table was an assortment of candles, bones, blood and other ritual items. It was an altar.

"Boys," came a sweet, feminine voice, "So glad you could make it."

Sam and Dean spun around so fast it nearly gave them whiplash, their guns pointed steadily towards the woman's head. Only she wasn't a woman at all.

"Now, now, I don't think we'll be needing those," she said calmly. With a flick of her wrist, the guns were wrenched from their hands and fell uselessly to the sides of the room.

"What do you want bitch?" Dean spat at her.

"Mind your manners, I might get offended," she put her hand to her chest in mock hurt.

"Yeah, well, maybe I couldn't give a crap about your so-called feelings," Dean's comebacks were sparkling with wit as usual, "if you even have any."

"Ouch," she laughed. "But I've had enough chitchat for one day, it's time you boys shut up and started to become useful."

She flicked her wrists again and Sam felt himself be flung backwards. He hit the wall painfully and groaned. Milliseconds later, Dean thudded next to him with a sickening crunch.

"God dammit!" Dean yelled, obviously in pain.

"Come now, you know I don't like that word," the demon smiled, deceptively sweet.

"You won't like my foot up your ass either," Dean grunted in frustration, fighting against the invisible force that held him.

The demon laughed.

"What do you want from us?" Sam demanded. He had grown tired of Dean's random insults; they never got them anywhere, other than in trouble.

"Well that's really quite simple," the demon sauntered closer to Sam, running a hand over his cheek, Sam tried his best to wriggle free from her touch but he could barely move.

"You see, everyone keeps talking about this big battle with Michael and Lucifer," she continued, walking away from Sam, "and about the chosen vessels."

She smiled knowingly at the brothers.

"All I keep hearing is about prophecies and sticking to what is written and blah, blah, blah. Problem is, I don't much feel like sticking to scripture. I mean, we're demons! What's the point of being a demon if you stick to 'God's plan'?"

Sam and Dean exchanged glances, neither liked where this was going.

"So I figure," the demon continued with a shrug, "Why not upend the balance? Given how we're liars and cheaters by nature, why not use that to our advantage? Plus, without his vessel, Michael's not going to be much of a problem at all."

She grinned at Dean and carefully picked up a knife from the altar. She held it as delicately as if it were a flower and walked to Dean as slowly as a funeral march.

"Leave him alone!" Sam shouted, redoubling his efforts to get free.

"Oh Sam," she giggled, "Don't you see? All the reasons you have for protesting are all the reasons I'm doing it in the first place.

"Once I cut out his heart," she placed the knife on Dean's shirt, "and offer it to Lucifer, you will have nothing to live for. So you will offer yourself to him when the time comes."

"I will never say yes to him!" Sam insisted, still struggling.

"Oh of course you won't, not whilst Dean is still there to be saved. But ask yourself this Sam Winchester," the demons voice got low, and her face was close to his, "Is a world without your beloved brother in really worth saving?"

Sam didn't respond. He couldn't. He knew Dean was staring at him, but he just couldn't bring himself to admit that she was right. He couldn't live without Dean, he didn't know how.

The demon laughed maniacally.

"I didn't think so," was all she said.

She moved back over to Dean and raised the knife above her head. The point was directed straight at his heart. Dean braced himself.

Then there was suddenly the familiar rush of wings. Castiel appeared behind the demon and ripped her away from the boys. She flew across the room and landed in a heap, before raising her head to glare angrily at the angel. Sam didn't think he'd been so happy to see anyone in his life.

Then he felt the pressure release and him and Dean fell to the floor.

"Go. Now," was all Cas said.

Sam didn't need asking twice, he grabbed Dean who was wincing in pain and dragged him out of the door. As they left the house Sam could hear the crashes and thumps of a demon on angel clash. He heaved Dean into the passenger seat. Then he grabbed the keys, started the car up and reversed her out of the driveway. Once he had turned around, he looked briefly in the rear-view mirror. There were bursts of light and rubble as the house was slowly torn apart by the raging battle within.