"Sammy?" Dean opened his eyes, feeling strangely disoriented, bright afternoon sunlight staining the room. It must be afternoon – why did Sammy let him sleep so late? He shook his head, his thoughts not entirely cohesive. That's when he felt it. It was too quiet. Something wasn't right. He sat up in bed and only then realized he was naked. He never slept naked, not unless he was with someone. But he'd gone to bed like normal last night. They were on a job. "Where are my clothes?"

Dean looked up and spotted his brother sitting in a chair angled toward his bed. Sammy's face was haggard, his eyes bloodshot, as if he'd not gotten any sleep at all. Dean noticed he was holding his .45 loosely in his hands. The case of silver bullets from the trunk of the Impala sat at his feet. Several of the bullets were missing. The feeling of 'things not right' shot up. "Sammy, are you all right? What the hell is going on? What's the gun for?"

His brother didn't look up. "Here." Sam pitched over his flat cell phone. "Look at the pictures."

Dean stared a moment longer at his brother then looked at the phone. He saw a picture of himself asleep in bed. "Well gross! Talk about awkward. Dude, why would you want a naked picture of me on your cell phone? Is there something you should be telling me?" Though his tone was light, Dean was feeling anything but inside.

"Could you, for once, just be serious for a minute?" Sam's voice cracked. Dean's feeling of unease took off like a rocket. "Check the picture before that one."

A rock had decided to start rattling around in the pit of his stomach. He was pretty sure whatever this was, he wasn't going to like it. He was right. The picture was blurred as if the action took place faster than the camera could handle. It was centered on the bed, just like the one with him in it, except instead of him lying there, there was a strange shifting shape. He could see black fur, claws, hairless skin, and a motion as if the figure was stretching. "What the hell?"

"Go back one more." Sammy spoke so quietly Dean almost didn't hear him. The gun was still in his brother's hand, not reassuring him in the least.

The new picture was of a black hunting cat of some sort splayed out on his bed. The weird feeling in his stomach turned hard. "That's a good one, Sammy. How'd you pull this off? Planning it for a while, were you? I thought we'd quit with the practical jokes for a bit."

A humorless bark echoed in the room. "I wish. Nothing would make me happier than for this to be some kind of sick joke. But it's not."

Dean cycled through the pictures again.

"I was here, Dean. I saw you change. That jaguar is you."

He remembered none of it. He could hardly believe it, even with proof. But there'd been those weird, dazzling dreams – the ones of the jungle, the giant tree, the caves that took you to the underworld – of running, swimming, hunting. Dread spread through him like a fever. "Have I, have I killed anyone?"

Sammy glanced up, his gaze filled with torment. "I don't know."

It squeezed Dean inside. Dammit! He threw back the covers and stood up. His left leg twinged with pain, so he looked down. His thigh was bandaged. He didn't remember being hurt. He sent a querying look Sam's way.

"I think someone took a pot shot at you. It's only a graze."

Nodding and saying nothing, Dean grabbed some shorts out of a drawer. "Where's the police scanner?"

Sammy pointed without looking to the far corner of the back dresser. It was the hand still holding the gun. "No weird homicide calls have come through. But it could just be that no one's come across any of the bodies yet."

The dead certainty in his brother's voice that it was only a matter of time stoked a flame of anger inside him. "Sammy, this is not the same as Madison." He grabbed the Q off the bed and shoved it at him. "Look at the pictures. I'm no werewolf! You saw it yourself. That's a full transformation. I don't understand it. I don't know what it means. I don't know how it happened. But it's not the same as hers! Use your head."

Sam roughly grabbed the cell phone from him and threw it away as he shot to his feet. "Don't you think I know that? What do you think I've been doing since I got you in here?" Dean took a step back, not having expected this much force in his brother's rebuttal. "It might not be exactly like what happened to her, but there are too many similarities to just dismiss it!" He started pacing, looking a lot like a caged version of what Dean was supposed to be. "You passed out the other day for no reason. You disappear after you fall asleep. You change shape. You have no recollection of what's happened or what you've done! What the hell else am I supposed to think?"

Dean wanted to make him stop pacing, or join him, or punch the wall, something! He had no more answers than his brother did. At least none that made much sense. "I've been having these really vivid dreams lately. Stuff I don't understand yet I know about. I always get the impression I'm looking for something. Maybe all this has something to do with that? Maybe if you did some research?"

Sammy sat back down, deflated. The hand with the gun hung between his knees as he rubbed at his face with the other. "I already have. I didn't find anything conclusive. I mean, there's lore all over the place, Indian, Maya, Olmec, Japanese. Gods do it, demons do it, almost every friggin' culture around the world has some type of myth about people changing shape into something else." Frustration dripped off him in waves. "But in all of them, those changing are aware of it. They're doing it because it's an ability they possess, because they want to transform. Werewolves are different, it's more like a disease or curse with them, it's something they can't control. And with you not even being aware that you're doing it…" He looked up, tears glinting in his eyes. "I ask again, what the hell else am I supposed to think?"

Dean sat down on the edge of the bed, feeling the weight already pressing his brother's shoulders. "You saw me in that other form and I didn't hurt you though, right? And I'm human right now. So for the moment everyone's safe – you, me, the people out there. Tonight…maybe tonight you can stay up, keep an eye on me. If I change, follow me, see what I do. If it looks like I'm going to hurt someone, then you do something about it, if not…then maybe we can learn something more about whatever the hell is going on."

His brother considered what he said and the weight suddenly seemed less heavy on them both. "Okay…" The muscle at Sam's jaw bulged, his brother still coiled tight, but there was less of an explosive edge to it.

"So can we put the gun away now?" Dean tried to sound as nonchalant about the request as he could manage. The whole thing was still creeping him out.

Sammy stared down at his hand as if having forgotten the automatic was there. He flicked on the safety and tucked it back behind his shirt, keeping his gaze lowered to the floor. "Sorry."

Dean heaved a sigh of relief. "You haven't eaten all day have you? With the vigil and all." He shook his head, knowing better. "Of course you haven't. Well I'm starved. Let me get dressed and we can get out of this stuffy place and have us a proper chow down. Tonight will be tonight and we'll worry about that when it gets here." He knew chances of that were slim, his brother an expert at brooding. But damn it if he wouldn't give it his best shot and keep him from thinking about it. Distracting Sam would distract him too, and he wanted some kind of distraction pretty bad right at the moment. Might be time to try something outrageous. He doubted Sam had ever tried riding a mechanical bull. Could be a blast.

He started digging in the drawers for some clothes.

"Dean…back at that haunted hotel in Connecticut…" He heard Sam hesitate, his indrawn breath uneven. "I forced a promise from you…that if I went dark side, that you'd take care of it. That you'd kill me… I'm, I'm sorry for that. It was totally selfish of me and I knew it. But just knowing there'd be an out if everything went totally wrong, if it turned out I wasn't strong enough…"

Dean barely dared breathe, let alone move. Sam's anguish as he spoke was palpable. This was one of the few things they never talked about, and the one promise Dean had had to face he could never bring himself to carry through on – even if it cost him his life.

"I didn't know what I was asking and I'm sorry. I just never knew, I never considered how it would make you feel… And now that I might have to do the same for you…"

Dean forced himself to turn around, a confident smile plastered on his face. "Well, we'll just have to make sure you never have to, don't we? And you won't. Not if I have anything to say about it. We're going to find out what this is about and fix it. That's all there's to it." And they would fix it, even if it was the last thing Dean ever did.