Humongous thanks (and cookies and sparkles) to sweet Meeshie for beta-ing for me.

Disclaimer: Supernatural does not belong to me.

Castiel gasped at the sudden stinging pain in his finger. Blood, vibrant red against his skin, welled in little beads along the length of the slice. He stared at his finger, then at the pages of the book that had betrayed him.

"Cas, you okay?" Dean asked absently from the couch across the library. He didn't even look up from the dusty old book in his hands.

Paper. Castiel's newly human body was so delicate that he'd damaged it with paper.

In the short time since he'd lost his grace, he'd been getting used to existence as a human and gradually learning his body's limits. He understood the threats of hunger and thirst. He knew exhaustion, cold, and the pain of injury. This body was weak and required a great deal of daily upkeep. It alarmed him sometimes how much focus and effort it took just to keep himself alive.

But this? How could he have known that paper could make him bleed? How could he possibly expect to survive trapped in a shell this fragile?

He was mortal now.

A cold dread prickled over his skin, and his stomach squeezed into an icy knot. He could die at any moment. Some seemingly innocent object – like this book – could kill him, and he'd never see it coming. Never recognize the danger.

"Cas?"

He'd existed for countless eons, and now it was over. He was going to die. There had been many times in his long life that he'd expected death. In the past few years, he'd actually died more than once and been prepared for it – welcomed it, even. But it was different then. It had been a choice. He'd chosen to risk his immortality.

Now there was no choice, and there was nothing he could do to stop it. It could happen tomorrow or next week or right this minute. He was going to die. This human flesh would rot, empty and lifeless, until nothing remained but dust.

And what would happen to his essence when he died? A queasiness gripped him as the possibilities flashed through his mind. His grace was gone, so he couldn't return to the Garden as angels did. He was human now, but did he have a human soul? He didn't think so. What if he simply ceased to exist? He would disappear into oblivion and be forgotten, as though he'd never existed at all.

The idea was horrifying.

His emotions ran hotter as a human. He would never get used to it. As an angel, he had feelings just like anyone else, but in this flesh and blood body, everything was more immediate – sharper and impossible to ignore. Confusing. He never seemed to feel a single emotion at a time. Jumbled up feelings surged through him at unexpected times, far more intense than he'd ever experienced before – raw and primal and often overwhelming. Right now, among other emotions he couldn't decipher, he identified despair and an irrational anger that defied explanation. And fear... No, that was panic.

"Cas! What the hell, man?"

A hand clapped down on his shoulder, and Castiel stumbled back from the unexpected touch, dropping the book to land with a smack on the library floor. His heartbeat thundered wildly in his ears. He clawed at his chest, trying to force his lungs to work, but there was no air. Blackness crept into the edges of his vision and his head spun. He couldn't breathe. He was going to suffocate this very minute, right here in the bunker where he should have been safe from all the dangers of the world. But nowhere was safe. And now the walls of this supposed haven were pressing in, squeezing the oxygen from the room. Castiel was dying.

"Hey, whoa, it's okay!" Dean's face swam into view in front of him. "I'm right here – you're okay!"

Castiel locked his eyes onto Dean's as he gasped for breath. The familiar green gaze was clouded with worry for him, and he clung to that knowledge in desperation. Dean wouldn't let anything happen to him. Dean would keep him safe.

Suddenly his body felt tingly and light, and his legs went wobbly as the blackness tried to swallow him. He clutched at a swirl of plaid flannel and felt himself supported as he sank weakly to his knees.

"Easy, easy...there you go. Take a breath. Put your head down, that's it. Now try to breathe with me, nice and slow, okay?"

Dean's voice was a soothing point of focus as Castiel regained control of his breathing. His heartbeat slowed to a more reasonable rate, and the dark spots in his vision faded, leaving him to stare at the scuffed hardwood of the library floor. The floor wasn't moving, and the walls weren't closing in. He wasn't dying after all.

He closed his eyes and sat upright when he was sure the dizziness had passed. The hand that had been smoothing comforting circles on his back was quickly withdrawn.

"You all right?"

Opening his eyes to find Dean crouched beside him with concern and confusion evident in his expression, Castiel felt a quick flush of embarrassment at his panic. He nodded.

"Dude. Come on. What happened? 'Cause you went white as a corpse there for a second."

A shudder rolled through Castiel as a vision overtook his mind's eye of himself dead and buried, his body crushed under the weight of the earth as he rotted away, eaten to nothing by insects, bacteria, and time. As quickly as it had appeared, the vision shifted to his dead body burning on a hunters' funeral pyre, his skin blackening, cracking, splitting open as he burned to ash and blew away in the wind.

Dean's hand gripped his shoulder once more, pulling him out of the morbid thoughts and stopping the panic before it took hold again. "Cas, what's wrong, man? Talk to me."

Castiel opened his mouth to speak, but found he couldn't find words adequate to explain his terror. Closing his mouth again, he shook his head helplessly.

"Cas..." Dean trailed off, pulling his hand back to ruffle through his short hair.

Shifting his weight to take the pressure off his knees on the unforgiving hardwood, Castiel considered how to explain the inexplicable. Dean was human. Surely someone who'd never known anything but a mortal existence couldn't understand the ex-angel's fear. "I got a papercut."

Dean blinked at him blankly for a moment. "Sorry, what?"

Castiel glared down at his finger before holding it out to show Dean the cut. Now that his panic had ebbed, Castiel could see how minor the injury truly was, and embarrassment flushed hot over his skin once more.

"That? It ain't even bleeding," Dean observed.

Snatching his hand back, Castiel wrapped his fingers into a tight fist, hiding away the evidence of his emotional weakness. "It was," he mumbled.

A wrinkle marred the line of Dean's brows as he studied Castiel like some kind of baffling science experiment. "I don't get it."

"You're human," Castiel clipped out, suddenly defensive. "I would not expect you to understand." Pushing himself to his feet, he scooped up his book again and began flipping through the pages. Best to face the dangers head-on.

Dean shot to his feet and grabbed the book, snapped it shut, and slapped it down onto the table. Anger gave his jaw a hard edge. "Excuse me, Mr. Holier-than-thou! Maybe I'm only human, but I'm trying to help here!"

"That's not—"

"And may I remind you that you're human now, too – not some high and mighty wing jockey!"

Dean's words felt like an accusation and cut Castiel to the quick. All the fiery tension cooled, and Castiel's shoulders slumped. "Exactly," he acknowledged as he turned to seek out the solitude of his room, either to reflect on his new found fears or hide from them. He was uncertain which.

Before he took two steps, Dean blocked his path, looking contrite. "Whoa, whoa, hang on! Look, I'm sorry, man, I'm doing my best here. I just don't understand what the hell's wrong. Throw me a bone, all right? What's so big about a papercut?"

Castiel paused, feeling so brittle he couldn't push his way past Dean for fear of shattering. He lifted his gaze to Dean's face, searching his eyes for answers to questions that couldn't be encompassed by words. "I'm dying."

Those clear green eyes widened in alarm. "What? Why? How?"

"I'm mortal now. I will die, and I can't stop it, Dean."

Confusion passed over Dean's features before realization dawned. "You mean you're going to die eventually. Like, someday, but not right this minute," he clarified.

A flash of anger sent heat prickling up Castiel's neck and into his cheeks. "I don't know, Dean! That's just it! Death is coming for me. I will die and rot and cease to exist. You call me human, but I'm not. I'm mortal, yes, but not human. I have no soul, Dean! No soul to move on from this place. When I die, there will be no Heaven for me. No Hell, no Purgatory. No afterlife at all! Just nothingness!"

His agitation grew as he spoke, and by the time his words choked off, he was shaking again, and his breath was coming in sharp gasps.

Dean stepped forward to place steadying hands on his shoulders. "Hey, Cas, settle down, man. Breathe."

But Castiel couldn't find any calm this time. Furious at the unfairness of the universe and his helplessness in the face of it he gripped the collar of Dean's flannel in both fists, emphasizing his words with an occasional shake. "It's not okay! You have no idea. You cannot possibly understand. Maybe I die tomorrow, maybe in fifty years. But it doesn't matter! Half a minute or half a century, compared to my life as an angel, it's a heartbeat to me. A blink of the eye. Can't you see? I'm already dead! I'm just not gone yet!"

Shoving Dean roughly to one side, Castiel stormed from the library and headed for the iron staircase leading out of the bunker. As he passed the doorway to the kitchen, he collided with Sam, who was emerging with a plate full of sandwiches. Castiel didn't stop, despite the clatter of the plate hitting the floor, and he ran up the steps two at a time. Behind him, he heard Dean calling his name and Sam demanding to know what was happening.

"Existential crisis of the century," Dean called back to his brother as he pounded up the stairs.

Castiel burst through the bunker's front door and fled down the road, with no thought other than to escape the suffocating confines of the Winchesters' home. He jogged a short way before he was forced to stop, bent over with his hands on his knees, sucking air. Black spots sparkled in the edges of his vision once again, and a horrible churning in his midsection suddenly made him think he might get to experience vomiting before he died. A cold, clammy sweat broke out over his skin.

"Cas!" Dean had caught up and now leaned down to peer into Castiel's face. His hand came to rest at the center of Castiel's back, and the ex-angel closed his eyes to focus on that point of contact as a way to distract from the nausea.

"Ah, crap. Are you gonna barf? You look like you're gonna barf," Dean said.

Dean wasn't wrong. Castiel's stomach rebelled, and he threw up twice into the dirt and gravel at the side of the road. As he bent over coughing and gagging, Dean stood beside him – far enough back to protect his shoes – and offered a steady stream of reassurances and a hand rubbing between his shoulders.

Castiel spit one last time onto the ground and tentatively straightened up, wobbling slightly.

Dean caught him by the shoulders and looked intently into his face, but Castiel wouldn't meet his eyes. Dean brushed Castiel's hair back from his face and swiped a thumb over his cheek. It was wet. Castiel frowned. Tears? He'd never cried before. He hadn't realized he could.

Dean asked, "Hey, buddy. You done puking?"

Castiel nodded weakly, so Dean continued, "Good. Let's get you back inside, okay? Come on."

They turned to go back, but Castiel stumbled on his tottery legs. Dean slid an arm around him and pulled Castiel's arm over his shoulder, gently supporting him the short distance to the bunker. When they got back inside, Sam was still cleaning up the bits of sandwich from the floor. He glanced up at the two of them with a rebuke on his lips, but Dean cut him off with a shake of his head and a grunted, "Later, Sammy."

Dean took them to the bathroom by the living quarters and stopped at the sink, leaving Castiel propped against the counter. He ran a glass of water and held it out. "Rinse your mouth and spit into the sink. You'll thank me later. If you're thirsty after, you can drink the rest."

Castiel took the glass and did as he was told. Dean didn't have to wait until later for him to be grateful for the cool, clear water, though. His mouth tasted awful.

Bustling around, Dean busied himself wetting and wringing out a washcloth while Castiel finished his water. Then he led the way back down the hall to the room Castiel had been using and ushered him inside.

As he closed the door behind them, Dean lifted his chin toward the bed and said, "Sit."

Castiel sat gingerly at the end of the bed, waiting for the lecture he was sure to come.

But Dean just turned and leaned back against the door, gnawing on his lower lip as he regarded Castiel thoughtfully. Finally, he tossed the dampened washcloth to him.

Uncertain what he was supposed to do with it, Castiel glanced up at Dean who explained, "For your face."

Castiel frowned. Was something wrong with his face?

Dean gave a long-suffering sigh and dragged the wooden chair from the corner of the room to the end of the bed. "Forget it." He plucked the washcloth from Castiel's hand as he dropped into the chair in front of him. "Just come here."

Dean took Castiel's shoulder, encouraging him to lean forward. He pressed the flat of the cloth to Castiel's forehead – the coolness felt wonderful against his skin, calming the flush and washing away the clammy sweat that still clung to him. Castiel closed his eyes and leaned into it, sighing in relief. Dean swept the cloth in brisk but gentle strokes over his brow, down to his temples, and across the bridge of his nose. Castiel's muscles began to relax, the soothing touch calming him and easing the tension from his body. Not since he'd lost his grace and become human had Castiel felt so centered and grounded.

Cheekbones. Jaw. Throat. As Dean continued his ministrations, the strokes of the cool cloth gradually slowed. Then Castiel felt the drag of the cloth pull at his lower lip as it was swept across his chin. The gentle movements stilled, and the fingers that gripped his shoulder now tightened almost imperceptibly.

Castiel opened his eyes to find Dean watching him raptly. The expression on Dean's face was one Castiel had seen directed his way before, though he'd never been able to assign a meaning to it. Usually, when he would catch a glimpse of Dean staring at him with that look, he would turn hurriedly away before Castiel had a chance to work out what it meant. This time, however, Dean didn't break away. The guardedness that often gave an edge to his features was gone, softening the fine lines around his eyes and releasing the usually taut muscles along his jaw. He looked younger. Open. Vulnerable.

The moment stretched until Castiel no longer felt grounded, but oddly nervous. He swallowed, trying to relieve the sudden dryness in his mouth, and Dean's gaze shifted down to follow the movement. That seemed to break the spell that had thickened the air in the room, because Dean suddenly dropped his hands and pushed his chair back to put a few extra inches distance between himself and Castiel.

"So, uh..." Dean began, while folding and re-folding the washcloth in his hands. "Doing better? Feeling okay?"

Castiel swallowed again, but his mouth remained dry. His nerves hummed and his stomach was jittery, but it didn't feel the same as before when he threw up, much to his relief. "Yes, Dean. I feel better."

Dean fiddled with the washcloth a moment longer, then draped it over a corner of the chair back. "You wanna talk about it?" he asked.

A shiver ran down Castiel's spine. For a moment he'd been distracted, but Dean's question brought his fear back with a sickening jolt. "No."

"Okay," Dean said with a conciliatory shrug. "But you know it's normal, right? Existential fears. Pretty much everybody gets freaked out about it at one time or another."

Castiel frowned, puzzled. "But...humans are mortal. You're born, and you die. It's what humans do. Why would you fear something so natural to you?"

Dean laughed, but it was darker than just humor. "It might be natural, but that don't mean we have to like it." His eyes lost focus for a moment, his thoughts taking him somewhere far away even as he smiled at Castiel's confusion.

"But after you die, you will go to Heaven."

Dean's shoulder lifted in another half-hearted shrug. "Most of us don't know that for sure. And even so, we fight like hell to stay alive as long as possible. Contrary nature of humans, I guess. Besides," he added with a wry smirk, "ain't nothing saying we have to make sense."

Castiel nodded his agreement, then paused as a thought struck him. "All humans feel this?"

"Pretty much, yeah. At some point or another."

"Even you?"

When Dean finally met his gaze again, his eyes brimmed with some unidentifiable emotion. A tic in his cheek belied the strength of that emotion, though his face remained mostly still. "Yeah, even me."

"When?"

For a long moment, Dean didn't react, and Castiel feared he'd overstepped the bounds of their friendship. But finally Dean leaned back in his chair and raked his fingers through his hair, disturbing its usual arrangement. Blowing out a breath, he dragged his hands back down his face. "Look, I've never talked about this to anyone. Sam was too young to remember, and he doesn't need to know. This stays between us, understand?"

"Very well."

"It doesn't leave this room, and we don't talk about it again!" Dean barked, eyebrows raised for emphasis.

"Of course," Castiel confirmed.

Despite Castiel's assurances, Dean still seemed to have trouble sharing his thoughts. He made several aborted attempts to speak, his throat working but producing no sound. Finally, he stood and paced the small room, which seemed to settle him a little.

"My mom died when I was four. I don't know if angels are ever kids or if they just poof into existence all grown up or what, but four years old is too damn young to understand what death means."

Once the words started coming, it seemed to get easier for him to keep going. "After the fire, things were rough. This was before Dad figured out about Yellow-Eyes, before he started hunting. He was a mess, but I was too little to understand what'd happened. I kept asking him when Mom was coming back, but he just said that she wasn't. All I wanted was my mom, but she never came."

Dean's voice broke, and he stopped, eyes on the floor as he regained control. At last he continued. "I started thinking maybe she was staying away because I'd done something bad, and she was mad at me. So I tried to be good. I put away my toys and ate my green beans without a fuss and went to bed when I was told, but she still didn't come back. I thought I wasn't being good enough, so I tried harder. I brushed my teeth, took care of Sam, and didn't cry when I was sad or hurt. I did everything I could think of so that Mom would come home."

Tears filled Dean's eyes and he tried to brush them away surreptitiously. "I asked Dad why Mom stayed away even though I was doing my best, and he... He told me that Mom was never, ever coming back. That I could never be good enough to make Mom come back."

His voice trembled along with his lip, and he didn't try to stop the tears anymore. They flowed freely down his cheeks and collected to drip off the end of his chin. Castiel felt tears burning in his own eyes for the second time that day, spilling over to match Dean's.

"Eventually, I understood that she couldn't come back, not ever, no matter how much I wanted it. She hadn't left because I was bad. Instead I thought the fire came and took her because I was bad. I got scared it was gonna come back and take Dad or Sam away forever, too."

Dean dropped heavily back into the chair in front of Castiel before continuing softly. "And then it dawned on me that the fire might get me, and I pretty much lost my shit. I was scared to death – total screaming Looney Tunes hysterical. For weeks, all I could think about was the fire that was coming to kill me. Dad had started hunting by then, and he didn't know what the hell to do with me, so he packed up me and Sam and dumped us off with Pastor Jim, who eventually got me calmed down and sorted out. I never bought in to the whole God thing, but he helped me let go of the fear."

Dean threw Castiel a look so sad, it nearly tore the ex-angel's heart in two. "I was so scared, Cas. It paralyzed me. It took over my life, and you can't let it do that to you."

Castiel leaned forward, needing to reassure his friend, comfort him. "Dean, you were just a child."

"Yeah, I was a little kid, but you've been human for less time than I'd been. It's okay to be afraid – it's normal. Just don't let it rule your life."

"I understand," Castiel acknowledged. Intellectually, he did understand, but he was fairly certain that even people accustomed to the intensity of human emotions would have difficulty controlling a panic attack.

Dean nudged Castiel's knee with his own. "It's okay. Really."

He nodded mutely.

"It's not the dying part that's freaking you out, is it?" Dean asked quietly.

Castiel looked up, startled. He shook his head.

"...Cas?"

"Your mother died, but she's in Heaven now. And you, too, will have Heaven as your afterlife, but I'll have nothing. After I die, I'll be forgotten. I may as well never have existed at all."

"Cas, that's not true. I don't know what'll happen to you when you die, but there's no way in hell you haven't made a mark on the world. Our lives suck a lot of the time, but we've done plenty of good. And you've been around practically forever, right? Answering prayers, performing miracles? Helped derail the freakin' apocalypse? I mean, come on! You've made a difference."

Dean's reassurances rang hollow, though. Guilt and regret tore through Castiel as he thought through the last few years. "Any good I may have accomplished is far outweighed by the bad. If I do leave any sort of legacy on Heaven and Earth, it's one of pain and death. I've killed so many. Made so many mistakes."

"Cas..." After a tiny hesitation, Dean reached out to place his palm on Castiel's knee and gave a squeeze. "Look, we all have a long-ass history of making terrible choices, but we've always done our best. Maybe things don't always end up the way we want, but we're trying to do right. And when we screw up, we damn well try to fix it."

Castiel focused on the hand at his knee, and tried to let Dean's words comfort him, but it wasn't working. "It doesn't matter, Dean. I don't matter. I'm not an angel anymore. I'm weak – I'm not even truly human. I'm nothing. Whatever I've done, it's over now."

"Whoa, hey now." Dean tightened his grip on Castiel's knee. "You're not nothing. Nobody gives a crap whether or not you've got angel superpowers. We care about you. You do matter. You matter to me."

Blinking up more in surprise at the statement than the sentiment, Castiel asked, "I do?"

"'Course you do, Cas!" Dean insisted, though he looked uncomfortable at being asked to repeat it. He pulled away, settling back in his chair and folding his arms in front of him, though whether that was meant to keep something out or hold something in, Castiel couldn't determine. "You're family."

Despite his misery, Castiel couldn't hold back a smile at Dean's obvious sincerity. "That means a lot to me, Dean. Thank you."

Dean's discomfort heightened, if his fidgeting were any cause to judge. "Yeah, well..."

They fell silent for a time. Castiel picked through the confusing barrage of emotions he was currently feeling, and decided it was hopeless trying to sort it all out. He was still fearful of his impending death, but at least the panic had eased. He watched as Dean slowly relaxed his posture, and was comforted by the thought that regardless of what happened to Castiel himself, at least Dean would find Heaven. He would have his family back again and be happy at last. Perhaps there would even be room in Dean's Heaven for memories of Castiel.

"When you reach Heaven someday...will you think of me from time to time?" Castiel watched Dean cautiously, afraid to be too hopeful, but he suddenly needed to know someone would remember him after he was gone.

Dean found his gaze and held it. The warm lamplight in the room caught the green and made his eyes shine clear as gemstones. "Of course I will." After a lingering moment, he dropped his gaze to the floor and added, "Heaven ain't Heaven without you."

Dumbstruck, Castiel could only stare.

But Dean didn't give him the opportunity to speak even had he been able. He jumped to his feet and dragged the wooden chair back to its place in the corner.

Clearing his throat loudly, Dean said, "Maybe you should rest for a bit. I'll check on you later, bring you some ginger tea – should settle your stomach." He gestured vaguely to indicate the general area of 'not in this room'. "I mean, I think Sam has some. Tea, that is. He's into all that girly stuff, so I'm pretty sure... Uh. Okay. I'll be back."

He slammed the door behind him as he escaped into the hallway.

Ignoring Dean's suggestion of rest, Castiel remained where he was and mulled over their conversation. Though he could do nothing to change his own fate, it was immensely comforting to know that Dean would not forget him. He was only one man, but he was the Righteous Man, and Castiel had felt peculiarly possessive of him from the very moment he'd laid hand on his beautiful, battered soul in Hell. Knowing he was important to Dean, too, made him unreasonably happy.

He glanced down at the red mark on his finger – the papercut that had set him on this careening emotional roller coaster. Yes, he was mortal now. Yes, his existence would soon be extinguished. But Dean would carry his memory with him forever.

Castiel looked down at the simple cut.

And smiled.