A/N: While most of my Season 5 stories follow a character progression from my first fic, "The Collector," this one is a direct sequel plot-wise. As a refresher: Crowley moved into Magnus's invisible mansion and made himself at home playing with that marvelous collection of supernatural artifacts. And now he's going to find himself in a wee bit of trouble because of it…

Disclaimer: I do not own Supernatural, I'm merely playing with it.

Huge thanks to 29-pieces-of-me for checking for consistencies and being a huge encouragement. Check out her fics for lots of TFW family feels. (You just have to survive some major hurt and killer cliffhangers before getting to the comfort, but it's worth it.)

Warnings: If you have severe snake phobia so that reading about swarms of them will be a trigger, this fic might not be for you.

Oh, and hello, my name is Aini, and I'm a Cas!whump-oholic.

Prologue

"Let's be reasonable about this," Crowley said amiably, even as he silently cursed opening the cage of the hag standing before him. Was she grateful that he had freed her from her prison? Did she feel indebted to his benevolence? Noo.

Instead, two dozen beady eyes fixed Crowley with predatory glares, forked tongues flicking in and out of their mouths. The crown of writhing snakes framed a woman's wrathful face. Slitted pupils haloed in red looked down a sharp nose to skewer the crossroads demon.

"I should disembowel you where you stand," she spat. One of the ruby serpents hissed to punctuate her sentence.

Crowley rolled his eyes. "That's my line, darling."

She sneered at him. Most of the monsters locked up in Magnus's zoo weren't worth Crowley's attention. Since taking over the deceased magician's invisible fortress, he'd been cleaning out the cells to ready them for his enemies, but the prize he'd discovered in one of the deep dark corners had been intriguing as a promising ally. Or so he'd thought.

"Listen," Crowley continued. "The Apocalypse has started since you've been away, and I'm sure you want to see the world end as much as I do. We can help each other."

Her eyes narrowed. "You are beneath me, Hell-spawn. I am a goddess!"

Crowley bit back a sigh. This woman was incorrigible. "Please," he scoffed. "You're a forgotten monster out of time. What do you plan to do on your own, leave a trail of petrified statues in your murderous wake? That's a sure-fire way to attract hunters."

"Hunters cannot kill me." She sniffed haughtily.

Crowley cocked a brow thoughtfully. "Not unless they're warded against you, as Magnus was. I know all of his little tricks…including that pesky binding ritual that had you licking his feet like a lap dog."

The gorgon pulled her lips back to bare her teeth. "You dare threaten me?" Several snake heads hissed and snapped their jaws.

Before Crowley could assure her that wasn't his intent and resume cajoling her into cooperating, she lunged, crooked fingers with tapered fingernails poised to slash at his face. He teleported away at the last second, reappearing behind her as she stumbled and stopped her momentum against a glass window of another display cage. Time to conclude negotiations, he supposed.

Crowley raised a hand, materializing a machete out of thin air, and swung it at the hag's neck. The gorgon must have caught the reflection, however, because she spun around and shot a bronze hand up to catch his arm. Crowley glowered as he tried to wrench free, but the wretch's strength was surprisingly a match for his own.

One of the snakes on her head lashed out, sinking fangs deep into tender flesh between his thumb and index finger. Fiery pain plunged through Crowley's hand, and the shock forced him to drop the blade.

The gorgon bent his wrist back until it cracked, and then shoved her other hand into his chest. Oxygen whooshed from his lungs as he flew backward through the air and hit the cement floor, sliding several feet before he knocked against the wall.

Grunting against a host of stabbing pains throughout his body, Crowley frantically got to his feet…and blinked at the empty hallway. Well, that had gone well.

He brushed the dirt off his suit, and winced as a dull throb pulsed through his palm. Crowley lifted his hand to inspect four, evenly-spaced puncture marks, deep and nearly black. There was no blood, but as he stared at the wound, the skin around the edges of the hole began turning a light gray.

"Bollocks."

Chapter 1

"It's not funny," Dean growled.

Sam barely contained a snicker as they trudged through a field under the light of a full moon. They'd just completed a salt and burn, and while the midnight beacon provided enough illumination to find their way back to the road where they'd parked the Impala, it hadn't shown the gnarled root jutting up from the ground…or the pile of cow shit just beyond it. Dean had stumbled upon it the hard way: literally.

Stupid ghost. It'd lunged at Sam, and of course Dean had to jump in with a swing of iron. But as the spirit dissipated in a violent swish, Dean's foot had snagged on the root and he'd gone down.

"I can't climb into my baby like this," he groused. Dark brown coated the front of his shirt and sleeves from when he'd thrashed to climb out of the gooey mess. His jeans were also smeared where he'd tried to wipe his hands clean. Oh god, the smell.

Sam snorted. "You really want to walk the six miles back to town?"

Dean grumbled under his breath. No, he didn't. He was exhausted, hungry, and reeked. But he was not soiling his baby.

"I'll call Cas to give me a lift." Dean reached for his pocket, but stopped himself before he could contaminate his phone. He never thought he'd wish for something as girly as hand disinfectant. "Uh, how about you call Cas."

Sam gave him a canted look. "You really want to ask Cas to be your personal taxi? You know his powers are slowly waning."

"But this is an emergency." He gestured to himself and then at the Impala.

Sam rolled his eyes. "I doubt Cas will agree."

"Just call him, will ya?"

With an exasperated head shake, Sam withdrew his phone and punched one of the speed dials. "Hey, Cas. No, everything's fine. If you're not busy, Dean would like you to pop over. He has something to ask you."

Dean shot his brother a dirty look for making it sound like they were sixth-grade girls passing notes in class. Sam merely smirked.

"Oh, well his phone's not working. Yeah. We're, uh, by a field just outside Beaumont, Utah." He scanned up and down the dirt road. "Maybe a mile south from 32 Creighton Drive."

Dean waited for the rush of wings to accompany the angel's arrival, though it wasn't as instantaneous as he was used to. He'd blame it on Sam's directions instead of the possibility that Cas's flying ability was beginning to suffer the ramifications of being cut off from Heaven.

It only took an extra thirty seconds or so for Cas to appear, the ends of his trench coat fluttering in the wake of invisible wings. He and Sam hung up their phones at the same time, and Cas swept his gaze over the Winchesters. His brow dipped slightly.

"What is that pungent odor?"

Sam snorted under his breath. "That would be Dean."

"Shut up, bitch." He had half a mind to wipe his hand over the crud on his shirt and slap Sam's face with it. But then there'd be no one to drive the Impala back to town, and he was not leaving his baby out here overnight.

"Dean had a run-in with some cow excrement," Sam said, barely keeping the smug look off his face. "Jerk," he added.

Cas studied Dean's appearance in the haloed glow of moonlight. "But you are uninjured?"

"Yeah, we're fine." Dean rolled his shoulder. "Um, mind zapping me back to the motel so I can get cleaned up?"

Cas's brow furrowed a fraction more, and he spent a long moment appraising Dean before glancing at the Impala, as though working out exactly the Winchester's reasoning behind the request, especially since Dean hadn't made it a secret how much he disliked flying "Angel Air."

Sam rolled his eyes skyward. "You can say no, Cas. Dean's just being a baby."

"You want to ride back in the car with me?" he snapped.

Sam closed his mouth as he seemed to think better of the idea. "Now that you mention it…" He grimaced and tossed Cas a half-apologetic, half-beseeching look.

The angel gave a minute head shake as though to himself, but stepped forward, two fingers outstretched toward Dean's forehead. Sam hastily blurted out the motel's address before Dean felt a shove and was briefly swallowed in a blinding vortex of wind. He staggered upright in the motel room, blinking away the lingering vertigo. Ugh. It was worth it though.

Cas took in their surroundings: the red plaid bedcovers, grainy wood-paneled walls displaying a mounted bass—thank god not the rubber one that sang—and blocky wooden dinette table. Another town, another wayward stop.

Dean immediately went for his duffel and pulled out a change of clothes. "I'm gonna hop in the shower."

Cas turned his head to look at him. "Is that all you needed?"

He winced, even though he couldn't really tell if Cas's bland tone held resentment or not. "I do appreciate it, man. So does Sam. He would've been bitching after five minutes stuck in a car with this." Dean gestured to himself.

Cas's expression pinched slightly. "Yes, you are quite unpleasant at the moment."

Dean didn't know whether to laugh or be offended. "Do you have somewhere to be? 'Cause you should stick around for a bit. Sam and I just finished a hunt, which means going out to unwind."

Cas pursed his lips. "If 'unwind' means you will be visiting a den of iniquity, then perhaps I should…take a rain ticket."

Dean shook his head. "Rain check, Cas. And relax, we'll go to a normal bar."

"But the den of iniquity sounds much more fun."

Dean jumped and whirled toward the source of the British voice, drawing his gun in one smooth motion. "Crowley?" He gaped in disbelief at the crossroads demon standing by the table, hands stuffed in his suit pockets. Dean had never expected to see the slimy salesman again after he'd moved into an invisible fortress to hide from Lucifer.

The demon wrinkled his nose at Dean. "Please tell me you weren't planning to go out smelling like that."

Dean lowered his gun. "What the hell do you want?"

"Is that any way to greet an old friend?"

"We're not friends," Dean growled. He didn't know what the hell they were. Not allies per se, though Crowley had helped them find the Colt—more or less. Never mind the gun hadn't actually worked on the Devil.

Crowley pulled one hand out of his pocket to press over his chest. "That hurts, Squirrel, after everything I've done for you."

"You mean turning tail and running when things went south. Twice?"

"Excuse me, but who saved all your lives in the end?"

Dean scowled. He wanted nothing more than to gank the demon right then and there, past truce be damned. But they were at a stalemate, for Dean's gun only had mere bullets, and Cas's smiting ability was nonexistent. Ruby's demon killing knife, unfortunately, was with Sam in the Impala on his way back.

"What do you want?" Cas asked calmly, though his stiff posture and mistrustful gaze belied his ease.

Crowley inclined his head. "I'd say you chaps owe me a favor."

Dean snorted. "You only helped us before to benefit yourself. We don't owe you jack."

Cas turned his head slightly to Dean. "Who is—"

Dean shot a hand up to cut off the angel, attention still on their uninvited guest. "Unless you have another way to ice the Devil, we're done here."

Crowley sighed in exasperation. "Look, a monster escaped from Magnus's zoo."

Dean stiffened. Sometimes he had nightmares of that place…and a gray-eyed Cas magically brainwashed by that douchebag Magnus. He cast a furtive glance at his friend, noticing how Cas's shoulders had gone slightly more rigid.

"I know you won't let your animosity toward me keep you from saving all those innocent people it could hurt," Crowley continued.

"Why do you care?"

Crowley lifted one shoulder lackadaisically. "She may have bitten me on her way out, and I need the antidote."

Dean raised his brows. A poison that could take out a demon? "You're dying?"

Crowley finally withdrew his other hand from his pocket and held it up. "In a manner of speaking."

Dean stared at the ashen skin, gray and cracked like crinkled newspaper. "What the hell is that?"

"You're turning to stone," Cas spoke up.

"Give the angel a cookie," Crowley snipped. "Now, can we discuss hunting down the gorgon?"

Dean frowned. "The what?"

Crowley rolled his eyes. "Don't they teach you any of the classics in hunter school? Gorgon: hideous woman with a head full of snakes."

Dean felt a flash of indignation before he processed Crowley's full sentence. "Let me get this straight, Medusa gave you a hickey so you decide to show up on our doorstep and ask us to get you some antibiotic ointment?"

"Actually, it was Stheno, Medusa's psychotic older sister."

Dean blinked at that, but then started shaking his head. "Whatever. You're the one who moved into that mansion. Clean up your own mess."

Crowley sighed, and swept his gaze around the room. "Where's your moose?"

Dean snorted. "Not here. And don't count on his sympathy."

Crowley angled a knowing look at Dean. "Sympathy? No, your brother has a more significant use than that." He pursed his lips. "However, since he is not here at the moment, I believe a substitute will work just as well."

Dean didn't see the gun materialize in Crowley's hand until the demon's arm was halfway raised. A crack split the air, and Dean flinched, braced for fiery agony to rip through his body. It never came, but he saw Cas jerk and stumble back a step. The angel dropped his gaze to his left shoulder, brow creasing in puzzlement as a splotch of red began seeping through his coat.

"You son-of-a-bitch." Dean whipped his gun back toward Crowley, mindful that his ammo still wouldn't do any lasting harm to the demon.

Crowley lifted his hands, pistol dangling from one finger through the trigger ring. "Down, Squirrel, it was a harmless lead bullet."

"Cas?" Dean called worriedly, wanting to check the damage but unable to take his eyes off the threat in the room. Dammit, he was going to kill Crowley.

"I'm fine," Cas said gruffly, voice sounding strained.

"What the hell was that for?" Dean shouted at the demon.

"Consider it motivation."

"You shoot Cas for fun and think there's any chance in hell we'll help you now?" Dean stepped right up to Crowley and pressed the barrel of his handgun to the demon's forehead. Whether it would kill him or not, Dean should still shoot him between the eyes on principle.

"Oh, did I say harmless?" A smug smirk twitched the corners of Crowley's lips. "There is the poison that bullet was laced with."

Dean's blood ran cold. "What?"

The demon flicked his gaze to Castiel. "It's a slow-acting venom with a timetable similar to my own. Actually, this works out better because now Moose won't be laid up and you both can work on hunting the gorgon."

Dean shot a panicked glance over his shoulder.

"You're lying," Cas said.

"I'm never without a contingency plan," Crowley said pleasantly. "So while I'd planned to infect Winchester Number Two, I made sure to pick a poison that would work on all kinds of entities." He looked back at Dean. "Including the angel that follows you two around like a lost puppy."

It took every ounce of strength for Dean not to pull the trigger right then. Maybe Crowley was bluffing about a poison that could take out an angel, maybe he wasn't. Either way though, Cas was cut off from Heaven and most of his powers, which left him vulnerable to things he'd never had to be wary of in the past.

Dean grabbed Crowley by the lapels of his suit jacket and slammed him back against the wall, keeping his gun pressed firmly against his head so as to leave an indentation.

"What's the cure?" he snarled.

Crowley lifted his infected hand, pores dilated like gray stucco, and pushed Dean's grip down from his neck. The hunter jerked away from the cold, gravelly contact, belatedly hoping the venom wasn't contagious.

"Not how this works, mate," Crowley said. "A cure for a cure; that's the arrangement." He frowned as he peered over Dean's shoulder. "Ah, perhaps you should pull the bullet out first."

Dean whipped his head around to glance at Cas, who had gone a few shades too white and was swaying where he stood as he stared at the bullet wound. Bright crimson now covered his entire shoulder and part way down one side of his chest.

Forgetting Crowley, Dean hurried to the angel's side and gripped his other arm. "Cas?"

Castiel lifted his head and blinked owlishly at him. "It won't heal."