Castiel was alerted to the older Winchester's distress early in the morning. He jumped to his feet, immediately concerned by the shout of pain and shattering glass he heard from the room next door. Rounding the corner as fast as he could, his coat billowing around him, he came to find Dean kneeling in the middle of the room, dripping blood and what appeared to be water.

Cas walked in, somewhat tentatively, one hand up in a motion of calm to Dean, the other clutching his angel blade. He looked around the room carefully, identifying the source of the broken glass. The mirror in the room was smashed to bits, and he followed the blood trail back to Dean, connecting the sound with his newfound injuries.

The angel hadn't quite made it to Dean when he heard the door behind him swing open further, and Sam burst in. The young hunter didn't waste the same time Cas did on caution. He instead crashed to his knees beside his brother, immediately inspecting the scene, trying to put the pieces together. "Dean!? What happened."

Dean pulled back from Sam's touch violently. He pushed away Sam's renewed attempt to touch his shoulder. "Stay back!"

"Dean, what is it? What happened?"

Both Cas and Sam watched as Dean uncurled his right arm from where it had been protectively over his side. He turned it, as if to show them something, but aside from the bloodied hands, neither of them could see whatever it was he seemed intent on showing. "I don't know why it's back."

"Why what's back?" Sam asked gently, a little shaken by the scene. "Dean what-" He tried to put his hand on Dean's shoulder again and Dean slapped him off, standing and scrambling away.

Sam watched as Dean splashed himself again from an open flask, and Sam recognized that the water all over his brother was just holy water. Dean winced from the water, turning his eyes towards Sam with such desperate fear. "I don't know why I'm-"

"Why you're-" Sam stiffened. "You think you're…" He wasn't… was he?

Dean looked away, sure he wasn't able to hide his black eyes with this emotional stress. He didn't want his brother looking at him like this. He didn't want to trigger whenever he would lose control, lose this compassion for his family.

"Dean, you aren't a demon." Cas cut in firmly.

"Then how do you explain the holy water!?" Dean snapped, rage swelling inside him in a last ditch effort to avoid his fear. "The black eyes? The goddamn mark reappearing?"

"Dean you don't have black eyes, and there is no mark on your arm." Cas continued, his voice never raising or faltering. "And the holy water isn't burning you." Dean flinched, but he let Cas approach him, feeling safer than letting Sam anywhere in the line of fire. Castiel grabbed his hand, turning it to show the hunter.

Dean looked down at his arm, the fog seeming to lift, and he was shocked to find the angel was correct. His arm was smooth and unmarred, free of the curse he was so sure had returned. He looked up, his eyes still wide with shock, and he looked over at Sam, hoping for some sort of answer.

Cas ran a hand over the hunter's injuries, the cuts from the glass vanishing in a flood of angelic healing. He then put a hand to Dean's head, trying to figure out what was happening inside the hunter's mind. He shook his head. "I still don't see any other injuries…"

Sam pushed past Cas, looking over Dean on his own, before pulling a somewhat disoriented Dean into a swift hug. "Don't scare me like that man." He breathed, trying to diffuse the tension with a bit of teasing, but falling short as his request sounded too sincere.

"Sorry." Dean mumbled before taking a deep breath and closing his eyes, trying to regain his composure. He clenched his fists tightly. "Cas, what the hell is going on? Why is it still getting worse?"

"This isn't from the smiting." Cas replied.

"Then what the hell is it?" Sam demanded.

"I don't know."

Dean sank back onto his bed, groaning as he moved his head too fast. He felt like he was shivering, but he knew he wasn't cold, since he still felt flushed and could count the beads of sweat threatening to cascade down his pale face. "Great."

Cas bridged the gap again, putting his hand back on Dean's head. "Not being attached to the full might of heaven, my ability to heal and see the body's inner workings has been diminished. Physical trauma is easy, the problem is never so well hidden. But your ailment is definitely an illness of some sort, and I can neither source it nor slow its progression."

Dean weakly pushed the angel's hand off his face. "Awesome." he muttered, closing his eyes and clenching his teeth, riding out another wave of nausea, successfully, for now. "Now what?"

"Now we figure out what's happening to you. If it's supernatural or just a normal illness…" Sam said with a sigh.

"When is something this miserable ever not been some supernatural pile of shit?" Dean asked, repressing a violent shudder.

"Good point." Sam agreed, his shoulders sagging a bit. He pulled the chair from the desk away and sank into it, giving his brother a bit of space, but being unwilling to go very far. "Alright, spell it out for me. List every symptom you have."

Dean managed to roll his eyes in spite of the dizzy spell that accompanied the action. "Lets see. The world is in a tailspin. My head feels a little like someone is shoving an axe through it. Every time I even think about food, my stomach threatens to exit my body entirely. It's a thousand degrees in here. My heart is running a marathon without me. Oh yeah, and there was that whole demon debacle what, ten minutes ago?"

"You still sound like you." Sam raised his eyebrows. "And this all came on last night?"

"It's been building up. My head started to hurt sometime during movie number two yesterday." He shook his head. "Felt off before that though, not sure why."

"And before the lockdown, when was the last time you were out of the bunker?"

"I picked up the pizza the evening before."

Sam frowned. "Not a lot of opportunity. And before?"

"Wrapping up the last business with the box of whatever for the thing." Dean dismissed the sentence with a gesture indicating his unwillingness to call up useless details.

"But I was with you that entire time, and I'm not sick." Sam agreed. He shook his head. "Alright, I'll start with the symptoms I guess. But first, we have got to get you to eat something." He frowned again at Dean's pained expression. "Or at least drink something. Come on man. You said yourself you've been sick all night. The least we can do is make sure you don't drop from something as simple as dehydration."

"Thanks mom." Dean groaned, sinking down on his bed so he was more horizontal. He only let himself lay there for a moment however before he forced himself into an upright sitting position, swinging his feet over the edge of the bed. With a groan, he pushed himself to his feet.

Sam offered a hand to steady him, but Dean slapped his hand away like a child. "I have two perfectly good feet, thank you." Sam raised his hands in surrender, stepping back and giving him a bit of space.

Cas pressed himself backwards as well, letting Dean pass him and shrug on his robe before heading into the hallway. He looked back to Sam, concern etched on his face.

"Watch him? Make sure he drinks some gatorade or something." Sam prompted, heading over to the mirror and beginning the task of cleaning up the room a bit before Dean could return. Before Cas left the room he stopped him. "And call me… if he starts seeing anything else…" He was still fairly shaken by his brother's recent break with reality.

Castiel nodded, following after the direction Dean went, and joining up with him in the kitchen.

Dean held up the red gatorade to Cas for his approval. When he received a nod he let himself sink onto one of the seats, reluctantly drinking it.

"Dean, I'm sorry I cannot do more for you."

The hunter let the tension slip out of his shoulders. He let his breath out, closing eyes for a second. "Don't worry about it Cas. Thanks for healing my hands. And, you know." Confirming that I wasn't actually my worst nightmare again…

"If there was anywhere to be trapped with a potentially deadly supernatural cursed illness, the men of letter's bunker has to be the best place…" Castiel tried to comfort.

Dean snorted. "Yeah. I guess so." He managed a small grin, looking a bit more like himself in that moment.

Silence settled in comfortably for a few minutes before Cas interrupted it once again. "Is there anything I can do to help ease your discomfort?"

He sighed. "A whole bottle of painkillers? The good kind?"

"I don't think it is advisable for humans to consume an entire bottle of any type of pain medication."

"Yeah, you're probably right." Dean froze, his grip on his gatorade bottle tightening as he looked alert. "Do you smell that?"

Cas tensed, withdrawing his angel blade on instinct. He tried to detect what the hunter sensed.

"What is that sound?" Dean stood, reaching for his gun and cursing when he realized he hadn't grabbed it when he left his room.

"I don't hear anything…" Cas replied quietly.

Dean began to creep forward, speaking a little louder than necessary. "You telling me you don't hear whatever that is!?"

"Dean… there isn't any noise… or smells."

Dean shook his head, putting his hands up to his ears, as he reacted to the growing sound only he could hear.

Cas had put away his angel blade now and headed towards the door to the kitchen. Dean didn't hear him call to Sam down the hallway.

Sam came running to the kitchen just in time to see Dean crumple in the middle of the room. He could only watch in horror as his brother thrashed wildly, his body spasming as if he were being electrocuted. Sam's chest constricted, and he looked to Cas desperately for help. The only time he had ever seen his brother have a seizure, he was in an intensive care unit, and he was dying. But that time there had been droves of doctors and nurses to come answer the alarms and initiate lifesaving care. Despite his age, Sam felt like he was 8 years old again, too young and helpless to even begin to fix this situation.

It was Cas who moved first, thrusting his folded coat under the hunter's head, gently padding the hunter's head from smashing into the cold hard cement any longer than necessary. The movement sparked Sam's brain into working again, and he moved closer to Dean's side. He swallowed hard as he tried to remember if he was supposed to be shoving a belt or something in Dean's mouth so he didn't bite his own tongue off. He shook his head. That and holding them down… he didn't think he was supposed to do that. He instead fought against his brother's flailing limbs, doing his best to position his brother more on his side, allowing his airway to be clear even as he thrashed.

The minutes felt like hours, and just when Sam was starting to edge into mindless panic, his brother's convulsions ceased as quickly as they had started, leaving Dean limp on the ground in front of him.

Sam pushed his fingers to his brother's neck. Pulse, way too quick, but strong. He paused, tensing up as he realized he didn't hear Dean breathing. He put his hand in front of Dean's mouth and nose. Nothing. He tensed, grabbing Dean's shoulder and giving it a shake. "Dean?" He shook his brother again. "Dean!?"

Dean took a shuddering breath. Then another.

Sam let out a breath he didn't realize he was holding and sank back down in exhausted relief. "Dean?"

Dean groaned, a little bit of blood dripping out of his mouth from where he had cut his tongue during the episode. He opened his eyes halfway, not focusing on anything specific. "S'm?" He mumbled, not quite managing a complete word.

"Dean." Sam breathed, putting a hand on his brother's shoulder. "You with us?"

Cas noticed Dean's far off look and frowned. He didn't look 'with them'.

"Sam?" He asked, finally letting his eyes fall closer to his brother, but he couldn't command his eyes to focus on Sam, and they kept slipping past the younger hunter.

"Dean, I'm here. Cas too." Dean let his eyes slip closed again, but Sam shook his shoulders roughly. "No Dean, keep your eyes open. You can't fall asleep now."

"Why?" Dean asked softly, swallowing like he hadn't had water in days. Sam didn't feel comfortable offering him anything to drink yet though.

"You just had a seizure, man."

"What?" Dean tried to look at Sam again, confusion obvious in his expression.

"What's the last thing you remember?"

Dean didn't answer, his eyes looking downwards towards the ground.

Sam shook him again as he seemed to doze off again. "Stay awake."

"Why?"

Sam frowned. "You just had a seizure…" He repeated softly.

"Sam?"

This time Sam couldn't shake his brother awake when his eyes closed again. He looked up at Cas like a lost child.

4 chapters down, 4 to go! Thank you for reading, and double thanks to those of you who review!