A/N: Another AO3 original, in seven parts! This one's not quite done yet (Chapter Seven is still on the way), but I'd love to hear your feedback. Sam/Cas + lotsa crack + lotsa fluff = the weirdest (but strangely fun) thing I've ever written. This takes place in S05, shortly after the boys start hunting together again.

My memory of the S05 timeline is extremely shaky, so parts of this may not sync up with canon.

A Quantum of Solace

Chapter One

Sam supposed he shouldn't have been surprised that it was Castiel who found him.

The world was white and without form. His head hurt like a bitch. Actually, that wasn't really true—his head felt more or less like it was going to pop off and float away like an errant balloon, but that wasn't really the same as pain. It was his everything else that hurt: his chest screamed with the echoing impact of a fall from a long distance, his limbs felt like snapped toothpicks, and there was a stitch in his side the size of Texas.

Aside from the part where he was pretty sure he couldn't walk, it was just another day in the week for Sam Winchester. A Tuesday sort of day, but still. At least no one had choked him.

"Dean, you fucker," he muttered. His own voice sounded distant and faded to his ears, and he was pretty sure Dean wasn't anywhere in the vicinity anymore, but calling his brother an idiot meant he was at least in control of some of his faculties, and that was a plus. Sam had been more than willing to take a peaceful tack when it came to dealing with the local witch—it wasn't like they suspected her for the disappearances in town; they'd just entered her fairy tale-pretty cottage hoping to skim some kind of lead off her—but Dean had inexplicably decided to go off script, whipping out his gun and screaming at the lavender-haired woman even before she could ask what the hell two hunters were doing in her home.

Sam tried to reconstruct those last couple of seconds in his mind. It was hard going. The clearest thing he remembered was the look of shock and fear on the woman's face; as vivid as the purple hair and the purple clothes and the purple shades of chipped polish on her bitten-down fingernails. An anxious witch, then, Sam had thought, right before she looked in his direction with a rushed spell on her lips and vanished with a crack like a bat connecting with his head.

Needless to say, the world had vanished in that moment as well.

Sam finished taking stock of himself. He was still wearing his button-down plaid shirt, hastily rescued from the motel laundry room that morning when the child of the couple next door had decided she was going to be a lumberjack (or was that lumberjane?) for Halloween; still had all his weapons on him (including the gun he'd failed to draw, a visible gesture to the witch that not every hunter was all about shoot first and ask questions never; he would have to remember to thank Dean with a whack upside the head later). Other than the balloon-esque dimensions of his skull and the pain that was marching up and down his body with viciously stamping feet, Sam thought he was in pretty good shape.

Until he sat up, and looked around him, and the whiteness resolved into an actual picture.

Before he hadn't had time to really survey the living room. Now, every last detail was blown into impossible, hallucinatory proportion: shelves crowded with books and figurines stretched for what seemed like miles into the sky, tapered off at a pebbled ceiling from which hung cheerful paper lanterns the size of houses; the room's single couch, festooned with psychedelic flower patterns, rose behind him like a monolith; candles as tall as the Impala was long emitted powerful aromas of pumpkin spice. The front door—the very one he and Dean had come through—was still open, admitting an IMAX-worthy view of red and orange foliage sweeping across a quiet suburban street, while the last Harry Potter book lay open just inches from his feet, the typeset large enough that he was instantly spoilered to hell and back about the location of the final Horcrux.

It was very clear to Sam that he was dreaming. That, or the witch had gone and cast the one spell he really, really wished she hadn't.

Namely: the one that shrank people.

Comforting as it was, he had to abandon the it was all a dream line of thought when Dean's voice suddenly broke the silence, shouting Sam's name in the thunderous tones of a spooked, trumpeting elephant. And now his head did hurt. "I'M DOWN HERE. STOP YELLING," Sam screamed back, but Dean failed to heed his demand, or even to take notice of him, his voice growing more and more panicky each time he didn't hear a response to his call, moving from the bedroom to the kitchen and back into the den with enormous stomping feet. Not that Sam wasn't trying. For one instant he was hilariously (and sickly) reminded of a Doctor Seuss book—how had it gone, the one where all the little people had to yell to be heard? A person's a person no matter how small?

He could have made a joke about how Sam Winchester was no person, no matter what size he was; only now Dean was bringing out the big guns.

"Cas!" Fear lanced through Sam's chest as well as pain, and for no reason he could think of he was crawling under the couch, joining the company of a stuffed animal that would have been creepy even without being a hulking shape staring at him with glittering black eyes. The simple act of relocating left him feeling rubbery and drained, like he'd just completed a deadlifting set; it was all he could do not to collapse into the layers of dust and dirt streaking the floor. Clearly their witch didn't believe in vaccuuming, probably for reasons of being environmentally conscious or something. "Cas, I'm on 1660 Sheffield Drive in Chapel Hill, North Carolina. I don't care if you're in the Vatican bumping uglies with the Pope, you need to get down here and right the hell no—"

Sam didn't need to see Castiel manifest to know when the angel appeared next to Dean; the change in air pressure was impossible to mistake now that he was small enough to fit in someone's pocket, and the holiness his presence always commanded seemed even more immediate, more oppressive. (Although Sam knew that likely had nothing to do with his size and everything to do with Lucifer's increased presence in his dreams... not that he was going to give Dean any more reason to stress over him.) They hadn't seen Castiel in weeks, consumed as he was with his search for God; and Sam thought he could pinpoint exactly how peeved the angel was going to be now that Dean was interrupting the good fight.

He was right. "I'm not in the mood for your irreverence, Dean," Castiel said in irritated tones, his voice a deep rumble that swept over Sam's eardrums like the distant sound of bagpipes over rolling hills. Sam estimated that they were in the kitchen; he couldn't see them from his vantage point, but he could hear the thud of a knife connecting with cheap particle board: striking surfaces with sharp objects was an old nervous habit of Dean's. "What is the problem?"

"What do you think? It's Sam," his brother snapped, worry for Sam precluding any possibility of being civil to an angel of the Lord (or half-angel of the Lord, or whatever Cas was now). "The idiot went and got himself cursed—banished—I don't know, Luna Lovegood took off before I could get anything outta her—"

"I'm the idiot?" Sam retorted under his breath, not even bothering to suppress the childish need to defend himself in absentia. "For your information, that witch was clean. No dark magic, no hoodoo shit. If you hadn't come in with guns blazing like some Arnold reject—"

He regretted the words even before he felt the shift of Castiel's vast weight, and the angel was moving into the den with a slowness that seemed premeditated. Each click of his dress shoes on the wooden floor inspired a burgeoning sense of dread in the younger Winchester. He would have retreated further into the darkness but for his nearly non-functional legs, and the fatigue that seemed to be dragging him deeper and deeper into the depths with each passing second. "Dean," Cas said. "I hear him. Sam is still here."

"What?" Dean still sounded angry, but also more hopeful. "What'd he say?"

"I don't know. His voice sounds... thin. Far away. I believe he called you an idiot." Castiel sounded almost satisfied at the last.

"Can't you call up some of that angel juice and figure out where he is? I've looked everywhere, Cas." Dean's anger had transmuted into plain desperation. Sam could imagine the angel glaring at Dean with heavily tried patience.

"I don't know how many times I have explained this to you, Dean. I don't have angel juice anymore. Not like I once did. I only know that Sam is still somewhere in the vicinity." The steps grew closer, more purposeful. "I will help you look for him. Have you checked outside?"

The kitchen door slammed in reply. Sam could almost imagine Dean muttering as he wandered around the animal-themed topiary he'd heavily side-eyed pulling up the driveway ("could we have picked a freakier witch?" his brother asked with almost helpless outrage, to which Sam responded that he thought it was cute, and also that Dean should focus on not running over the mailbox). Dean's angel, for his part, walked calmly through the preternatural silence, even the click of his heels disappearing as he tread across a fluffy throw rug.

Dean's angel. And apparently those were all the words needed for Sam's vague uneasiness to morph into a full-fledged species of terror. He hadn't thought he was afraid of Castiel, but the angel had never been his biggest fan—because being a demonic vampire freak doesn't exactly make for a great first impression, genius—and he had long agonized over the knowledge that he was the reason Castiel was now a fugitive from his own home, his own family. Had had to endure the private hell of permanent separation from the Host, while he slowly lost every vestige of the power that had made him what he was.

Let the record show: Sam Winchester had fucked up. He'd thought he could stop Lucifer on his own, but the only thing he'd proven was that he was a dumb bastard with an enormous chip on his shoulder and enough hubris to match. Not to mention, the permanence of Lucifer's rising sort of depended on his continued existence.

It was no accident that Dean had been sent outside.

After all, Castiel had every reason to smash him like a bug.

Castiel was past the throw rug now. His foot fetched up against the Harry Potter book. Sam broke into a cold sweat and his migraine intensified on a withheld sneeze as the angel knelt to peer closer at it, casting a shadow that was long and deep enough to plunge everything into near-complete darkness. A moment later the angel picked up the book and moved it, as though setting it aside for closer inspection, and the resulting shaft of light revealed the most enormous hands Sam had ever seen. Delicately shaped and uncallused, but still: huge. The younger Winchester nearly made the mistake of crying out for Dean, but he stuffed the words down and prayed instead.

Please don't find me. Please don't find me.

Castiel paused. "That is a very unusual thing to pray to an angel," he said with slow graveness, and Sam nearly screamed for his sheer incompetence. He knelt in front of the couch once more. Sam couldn't see his face, which was just as well because he could barely fucking handle the sight of his hands. "Sam, I can hear you. You sound hurt. Dean says that the witch is gone; it's safe to come out." Silence. "Please. I don't know why you are hiding, but please show yourself to me. I can't tell what has been done to you, unless—"

"I." Sam nearly choked on the single syllable. The chilly sheen on his skin had gone arctic. He hadn't felt such gut-twisting terror since Ruby's revelation, and if he was going to die—well, he deserved it. If Castiel wanted to kill him, he was going to kill him, and it was the very definition of selfishness to wait until Dean potentially caught him in the act and had yet another reason to be traumatized by Heaven. "I'm going to try. Coming out, I mean. But." He swallowed hard. He wasn't sure thanks to the darkness, but he thought he might be going dizzy. "I, I can't move real fast..."

"Don't rush yourself," Castiel warned.

He sounded genuine enough. Sam braced himself, maneuvering as best he could on hands and knees past the bizarre landmark of the stuffed animal, past the entire sordid company of dust bunnies, ignoring the pain screaming through his limbs. Almost worse than the pain, though, was the nausea; dust and sweat made for a truly nasty combination. He shut his eyes as he came into the light, like a mole monster unfit to be seen outside its underground lair.

There was a brief intake of air above him. Well. He'd managed to surprise Cas. "Oh," the angel said. Whispered, now that he knew what was going on. Sam couldn't say he didn't appreciate it.

A long moment passed. "How are you feeling?" Cas finally asked.

Was that a serious question? "Um," Sam said.

Another long moment. The world spun beneath Sam's hands and knees; he focused on nothing but his own reflection in the polished wood, resolutely ignoring the oversized circus dimensions right outside his peripheral vision, ignoring the giant upon whose mercy he would live or die in the next few seconds.

"Um...?" Castiel prompted, sounding somewhat helpless. When no answer was forthcoming, he said: "Sam, may I look at you?"

No. Dear God, no. Not even with Dean would he have been prepared for that. "I—my head hurts, really bad," Sam said, relenting. "My whole body does. I can't walk."

Castiel made a low humming noise. The sound prompted Sam to instinctively turn his face towards it, and in an instant he was struck by vertigo, Castiel's form looming over him like a skyscraper, trenchcoat stark and angular and giving him the appearance of something straight out of The Iron Giant. He really should have just quit while he was behind, but like a train running off the tracks his gaze just kept going up and up and up, until finally it found Castiel's face.

Immediately his vision was shot through with blue. Well, that just figured. It was almost the only thing he'd noticed the first time he'd ever met Cas. At the time, he had thought it was beautiful. It still was, but now it also scared the shit out of him. Those pools—oceans—of water drew his eyes with a force that bordered on the magnetized. Castiel seemed to understand what was happening, his movements incredibly slow, as though conducted underwater. Sam was more certain than he'd been a minute ago that Castiel wasn't going to hurt him, but it was still so strange. He had long known Cas as the one to (in Dean's words) smite ass and take names, taking up his brother's cause with an efficiency that was as graceful as it was merciless; he didn't know how to reconcile that with the endlessly careful creature before him now.

When Castiel finally blinked, the sway of long dark lashes interrupting Sam's reverie, he was stunned to realize that the angel had stretched himself by tiny increments into a lying position, meaning his face now hung mere inches away, instead of mere feet. Sam's first thought was that Cas could really benefit from some chapstick. The second was how unfair it was that angels got to have perfect unmarred skin while he still had to deal with acne at the tender age of twenty-six.

Only by the third thought did he become fully aware of just how screwed he really was. He froze and an inaudible squeak of terror forced its way up his throat.

"Do not be alarmed," Castiel said.

His lips barely moved. Sam's eyes swung to them anyway, transfixed. Like a mouse caught between the cat's paws.

Then—completing the prey animal motif—he fell to the floor. Closed his eyes and pulled himself into a ball.

So this was it, then. He'd been caught sleeping, as it were; Bobby would probably have something to say about that. Or would have had something to say, if Sam wasn't about to die horribly right now.

I am so sorry, he thought. He wasn't sure to whom. Maybe to Bobby, or his dad. To Dean for sure. Or even Castiel—

Warmth sank into his bones, like steam from a hot bath. Sam was immediately confused. To his knowledge, this wasn't what being pulverized felt like. He dared to open one eye. Castiel's face still hovered above him, impossibly wide, his eyes closed in a picture of serene concentration. Sam could not quite comprehend what was happening; but as the warmth spread from his bones into his blood and finally seeped clean through to his skin, causing his spine to involuntarily unwind and his mind to relax, it came to him: Castiel was breathing on him.

It was the one thing he never expected, and his laugh was more like a sob. A snatch of a scene from a book he had loved as a child—a lion approaching a statue, bending its great head to breathe it back to life, imparting strength and dignity and wisdom far unequal to the person upon whom the gift was bestowed—flashed through his mind, eliciting a full-body shudder. The coolness of falling snow, the warm light of a lone lamppost, fauns that invited queens to tea and beavers that sat at sewing machines... "Cas," he muttered, as the pain faded away to a distant memory and his skin grew clean and clear. Castiel said nothing, just kept breathing in and out, and Sam felt his own chest surrender to the rise and fall of that calm, unhurried rhythm. Castiel's lips closed around one last swell and then his face was retreating with unbearable slowness, brilliant blue eyes opening to watch him with something like relief. Sam looked up into them, for a brief eternity just letting himself slip away, drift on the gentle waters.

At long last Castiel tipped his head to one side, and he spoke.

"Do you still feel pain, Sam?"

He was still whispering.

"No," Sam said. Already that dreamy feeling of stillness was beginning to fade, and he wished he could hold onto it for just a little more. "No, I'm all better." Then, shyly: "Thanks."

Castiel's head tipped in the other direction. Sam took this to mean that Castiel didn't particularly think he deserved thanks, but he wasn't about to take it back. "I'm glad. My Grace is... imperfect, these days. I could not rely on ordinary means of healing due to your—er, condition—and because of my own misgivings about my power."

"I'm sorry," Sam murmured. "It's my fault."

Castiel's brows knitted together like he wanted to argue, but he said nothing more, and he pushed himself back up to kneeling, every angle of him unfolding like origami as he resumed his initial unfathomable height. "Can you stand?" he asked.

He waited patiently as the young hunter extended a leg, gingerly tested his bearings. "I think so," he said after a moment. It took more than a few minutes to get to his feet and he was still a little wobbly, but Sam thought he managed it okay.

He nearly fell back on his ass when Cas extended his palm to him, clearly expecting him to hop aboard. It may have been a promontory of flesh and fingers he was staring at, but this was just like that time Dean had tried to sneak their underaged butts onto that shady-as-shit wooden coaster at Jersey Shore. He was neither ready nor enthused to exchange one death trap for another.

"Come," Castiel said simply. "I will convey you to your brother."

"You couldn't just—poof me?" Sam ventured timidly. Cas just gave him a look, and with a watery sigh Sam stepped forward, trying to summon those inner reserves of otherworldly strength Castiel had breathed into him. It helped a little bit, but not enough to stop the embarrassing little oh that popped out of his mouth as he tripped over the angel's thumb (easy to do when said thumb was at least as big as you were).

Castiel's hand was comfortable, and it was warm. Sitting in his palm, Sam felt a bit like a baby bird in a nest. Still: it was hardly safe. "I could do with a seatbelt," Sam muttered, more to be facetious than anything else, and started when Castiel's other hand came up and began to curl around him, fashioning just such a feature. Sam let himself be cradled in those exceedingly gentle fingers. He held onto Castiel's thumb, secured firmly around his waist, and didn't panic even when the angel drew his enfolded hands close to his chest. The distant thunder of a steady heartbeat roared in Sam's ears, and he smelled trees.

"Is this acceptable?" Castiel asked. Sam nodded. "We are moving now," he added, rather unnecessarily, and they rose. Sam's heart swooped in his stomach as his view gradually shifted to a full-scale panorama of the living room, like the moment the coaster had crested the top of a hundred-foot hill and then just sat there overlooking the beach, ratcheting up the tension in his seven-year-old heart. No amount of junk food from Dean afterward could dry Sam's tears, but Sam had to admit: this was kind of nice. He could distinguish the titles of books on Wiccan philosophy and practice, Meditations of Mystics Through the Ages, Communing with Mother Earth, How I Learned to Stop Worrying and Love my Tarot Deck; he nearly laughed when he saw that one of the carved figures acting as a bookend depicted a lion sitting peacefully on a rock. If he and the witch didn't walk in such monumentally opposed social circles, he thought they could have been friends.

Maybe they still could be. It's not like he ever thought he'd be friends with an angel, either. Provided, of course, she was willing to reverse the whole shrinking him down to the size of a thimble thing.

"You told Dean to go outside. Did you—um—did you know?"

"I suspected," Cas said. "I did not think he would react well."

Sam chuckled. "You got that right. Dean is gonna freak when he finds out. You know, uh," he added as they moved into the kitchen, "you're surprisingly good at this."

Surprise rippled gently through Castiel. "I suppose that's to be expected," he said after a moment. "I am accustomed to humans being of—of a certain height. In my true form, I am at least as tall as one of your skyscrapers. This arrangement is... you could say it's a return to form for me."

Well. There was really nothing Sam could say to that, other than that he had yet another reason to be awed by his brother's angel. "I'm glad one of us is taking this well," he said honestly. Then: "Thank you."

"You already said that," Cas reminded him.

"Yeah." Sam huffed a laugh. "I sort of thought you were going to kill me, so."

For an instant Cas actually stopped walking, surprise radiating from him once more. Then the angel gave a long, put-upon sigh. "Sam Winchester, you are ridiculous," he murmured with no small amount of irritated affection. "But you are also my friend. I am not inclined to kill you."

Friends.

They paused when they reached the back door. "So, tell me. How did this happen?" Castiel asked, and Sam proceeded to explain just how boneheaded his brother really was.