NB: This is the second part of my Tok'ra Apocalypse trilogy. Please read "Snakeheads" before beginning this one.

Warnings: This story is AU for both Supernatural and Stargate SG-1/Stargate Atlantis. Spoilers for Supernatural "The Devil You Know," "Two Minutes to Midnight," and all previous episodes of Season 5; there will be some lines from both episodes incorporated, but well within fair use. (I chose the title before "The Devil You Know" aired—at least, the phrase came to mind and stuck—so it's not a deliberate reference to a certain part of the canon story arc, but man, if it doesn't fit!) There are also references to SGA "Critical Mass," "Tao of Rodney," "The Seer," "The Shrine," "First Contact," and "Infection" and SPN "Croatoan," "Mystery Spot," "In the Beginning," and part of the Season 4 storyline.

Setting: Late April 2010—this 'verse's version of Supernatural "The Devil You Know" and "Two Minutes to Midnight," post-Stargate: Extinction and maybe Season 2-ish for Stargate Universe

A/N: Oversimplified, but just to avoid confusion: SGA Wraith [sic] are human-bug hybrids that suck humans' life force from their hearts through a feeding slit on the right palm; SPN wraiths [sic] are supernatural creatures that appear human (except in a mirror) and suck humans' brains dry through a retractable spine in the right wrist. Both can cause visual hallucinations. Neither is synonymous with Nazgûl. Todd is a Wraith, not a wraith. Also: I'll use "Sam" for Sam Winchester and "Carter" for Sam Carter except in unambiguous direct address.

Many thanks to my darling beta Ansostuff!

If Wishes Were Horsemen
By San Antonio Rose

Chapter 1
Heffalumps and Woozles

On the outskirts of a lonely Nevada town in the grey light of dawn, Sam and Dean Winchester had stopped to change into their suits at a convenience store and were on their way back out to the car when Dean's cell phone rang. At least, the ringtone came from his pocket. He didn't recall setting any of the numbers in his address book to ring with "Pretty Little Angel Eyes."

"Gabriel," Sam said instinctively.

Dean rolled his eyes and answered the phone.

"Dean!" came the obnoxiously cheerful archangel's voice. "How are the snakes?"

Dean sighed, made sure the parking lot was empty, and let his Tok'ra symbiote reply. "We are all well, thank you, Gabriel."

"Oh! Hey, Dishon, good to hear from you. I really need to talk to Dean, though."

"I am not certain he wishes to speak to you."

"He never does. But I've got important news."

"One moment, then." Dishon retreated, and Dean snapped, "What?"

"I found Castiel."

Dean's annoyance fled instantly at the mention of their lost angel friend. "Cas? Where? How is he? Is he okay?"

"Tulane Medical Center, unconscious, and no. That dumb stunt in Van Nuys really did a number on him; his grace is almost gone. The doctors tell me he appeared on a shrimping boat off Delacroix. They think he's brain dead, but his being a John Doe and not having a living will kept the administrators from pulling the plug long enough for me to get here and play the next-of-kin card. He's physically stable otherwise, and I'll do what I can for his grace, but... we may be here a while. I'm still not 100% myself, and it's not like the SGC docs could do much more for him."

Dean sighed. "Okay. We're still chasin' Pestilence across western Nevada. When Cas wakes up, call us and take him to Bobby's. We'll get there as soon as we can."

"I'll bring you some jambalaya," Gabriel promised and hung up.

"Cas?" Sam asked.

Dean repeated what Gabriel had told him.

Sam swore. "I don't think that healing device works on angels."

"Gabriel's there," Dean shrugged as they got into the Impala. "And we're here, almost two thousand miles away, and we need to catch Pestilence before the Croatoan virus gets loose."

"Fair enough," Sam conceded unhappily.

Dean's head bobbed, and Dishon added, "Dean is worried, too, Sam. But we cannot abandon this mission to keep vigil with Gabriel. It would be worse for both of you to sit idle there when you know there is work to be done here."

Sam nodded. "Salim's thinkin' the same thing. Guess you're all right." He sighed. "Okay. Let's go check out this flu outbreak."

Dishon returned control to Dean, who nodded once and started the car.

Something was up with the Winchesters. That was all that the British crossroads demon known as Crowley could conclude with any certainty. Something had happened to Sam and Dean that night at the Elysian Fields Hotel during the so-called summit of the gods, while he'd been dodging a roving band of daevas and couldn't monitor his supernatural bug in the Impala, that had left them with what seemed to be either multiple personality disorder or the strangest case of possession he'd ever encountered. It was that conclusion as much as their dubious scheme to force Lucifer back into Hell, assuming he'd pieced together the clues correctly, that made him decide to contact them that night when they passed close enough to his Nevada hideout in their search for Pestilence. But so far he'd seen nothing to explain what he'd been hearing—not until he brought the boys back to his lair and made his pitch regarding the hunt for the Horsemen's rings:

"I want in."

A lightning-quick head bob, and Sam's green-hazel eyes suddenly glowed briefly. It was all Crowley could do not to jump in alarma demon's eyes might change colour, but they never glowed.

"I would not make such demands of ones you have ill used, shol'vah," Sam spat in that strangely distorted voice Crowley had heard and puzzled over in recent days.

"Salim," Dean objected. "Name calling won't help."

Sam bowed his head briefly, and when he spoke again, his voice was normal. "Yeah, well, Salim's right."

"I know. I'm not disagreeing with either of you. Neither does Dishon. It still won't help." He turned back to Crowley. "You said you could get us Pestilence."

Crowley was now totally at sea regarding this Salim personality, especially considering that it had called him a traitor in Ancient Egyptian, but he forced himself to recover his composure and respond with his offer of Pestilence's front man. Dean looked thoughtfully at Crowley for a moment, and though the firelight from the hearth was dim, Crowley could swear he saw the flicker of an internal conference going on behind those green eyes.

"I've got a better idea," Dean said finally. "How about you give us this demon's coordinates, and we'll have a friend bring him straight here."

Crowley blinked. "A friend?"

A corner of Sam's mouth twitched upward in a humourless smile. "Another shol'vah. But one we can trust."

Castiel? Crowley wondered. No, it can't be. They would have said something if they'd found him and he was flight-worthy. He cleared his throat. "Well, if your friend can get by all the demons guarding our target..."

"Faster than you think," Dean confirmed.

"And he won't kill me on sight?"

"If we tell him not to."

Crowley sighed; he couldn't give away his real objection, not yet. Sam had already tried to kill him twice and might not miss again. "All right, then." He rattled off the coordinates for the company where Pestilence's henchman worked. "Niveus Pharmaceutical. The demon we want is in an office on the twelfth floor; he's vice president for distribution."

Dean nodded and reached into his jacket pocket as if to find a cell phone. "Wait here."

And the man strolled out, leaving Sam glaring daggers at Crowley, who began to wonder if this plan was such a smart idea after all.

"Colonel Carter?" Maj. Kevin Marks called across the bridge of the USS George Hammond. "We've got an incoming message on subspace. It's Dean Winchester."

"Open a channel," replied Col. Samantha Carter, coming in from a side corridor, followed by Teal'c of the Jaffa and Dr. Daniel Jackson. Marks made the connection by the time she got to the command chair. "Dean. What's happening?"

"Well, these swine flu outbreaks are definitely Pestilence omens, Colonel," Dean's voice came over the comm, "and we've got a line on a biotech company that's involved. One of the execs is a demon who's a travel agent for the Horsemen. Dishon thinks they might have ties to the Trust as well."

"What's the name of the company?"

"Niveus Pharmaceutical." Dean gave them the coordinates and the location of the demon's office.

Daniel frowned. "That's Cam's cousin Brady. Cam said he had some weird experience over Christmas break back in 2003, went back to Stanford and just about killed himself with drugs. Hasn't been the same since. But he got straightened out..." He paused. "Thanks to his best friend Sam."

Dean cursed quietly. "Crowley didn't mention that."

"Mitchell never mentioned Sam's last name," Daniel cautioned. "It could be a coincidence."

"With Sammy, nothing is a coincidence," Dean shot back before cursing under his breath again.

"We can ask when the Odyssey checks in next."

"Nah, I'll have gotten it out of Crowley by then."

"We'll contact the SGC," Carter interrupted. "There may be an NID team nearby that can arrest Brady."

"Bad idea," Dean replied. "Place is probably swarming with mooks; your people wouldn't make it out alive. Safest way is to beam somebody down to Brady's office, zat him, and beam him back here."

"Where's 'here'?"

"It's a safe house outside Silver Springs, Nevada." Dean gave her the location. "Give us about ten minutes to get set on this end, and beam down outside the house."

"Marks, do a sensor sweep," Carter ordered.

"Yes, ma'am." Marks pressed the requisite buttons and had a life-signs scan of the area on the main viewscreen in a matter of seconds.

"Dean, I'm reading three life signs at your location," Carter reported. "Two Tok'ra and one other."

"Yes, ma'am," Dean replied. "This is me walking around the front of the car—which, incidentally, we've just learned is bugged."

Carter watched the corresponding green dot move on the screen, apparently giving the Impala a wide berth. "Copy that," she replied.

"Sam and Crowley are inside."

"Roger. You're sure you can handle the prisoner there?"

"Yes, ma'am. It's better if he and Crowley know as little as possible about the SGC's involvement. We probably can't keep you off Hell's radar forever, but we shouldn't attract their attention to you any sooner than we have to."

"Understood."

"Oh, and Colonel, if and when you do take down Niveus, make sure your people take extreme hazmat precautions. There's a second, much deadlier virus Pestilence is keeping up his sleeve, and it's just possible that there are samples stashed at Niveus' labs."

Carter had a sudden flashback to the Prior plague. "Deadlier how?"

Dean sighed. "It's called Croatoan; it spreads by blood-to-blood contact; it turns people into murderous zombies within four hours; it was created by demons; and it's the devil's endgame. Oh, and Sam's immune to it. That's all we know."

Daniel frowned. "How do you know he's immune?"

"Someone in River Grove, Oregon, deliberately infected him."

"When was this?"

"Late 2006. Why?"

"If we can get those records, it might give us a place to start to develop a vaccine."

"I'm not sure we've got that kind of time."

"We could set up a time dilation field if we had to," Carter observed. "That would buy us a little time. Better yet, we can get Atlantis working on it; surely there's something in the Ancient database that would be useful."

"Well, we still want to gank Pestilence before the virus gets loose," Dean noted, "but I guess it wouldn't hurt to have a backup plan. Y'know, in case."

"Right. Okay, Dean, we'll send Teal'c to pick up Brady in ten minutes and beam him to your location. Be standing where you are now so we'll know we're not beaming them into your car."

"Copy that. Thanks, Colonel. Winchester out."

Daniel turned to Carter. "Be even faster if we had Niveus' records as well."

Carter nodded. "Have General O'Neill put Dr. Lee on it right away. You go see what you can find about River Grove, and have Dr. Lam make a copy of her report on the Winchesters' bloodwork to send to Carson Beckett. We'll grab a blood sample from Brady as well. The Atlantis dial-in is in twelve hours."

"Right."

"Marks?"

"Yes, ma'am," Marks nodded and beamed Daniel down to the SGC.

Carter activated the ship's intercom and ordered a medical team to the bridge. She then noticed that Teal'c continued to stare thoughtfully at the screen. "Is there a problem, Teal'c?"

"We have programmed our sensors to distinguish human life signs from both symbiote carriers and Wraith," the Jaffa observed. "Perhaps it will be possible to do the same for demons."

"Worth a shot. What do you think, Marks?"

"Theoretically, it should work once we identify any anomalous readings from Col. Mitchell's cousin," shrugged Marks, who had helped Drs. Rodney McKay and Radek Zelenka to modify the sensors on the USS Daedalus to detect Wraith after the siege of Atlantis five years earlier. "But we don't know yet if demonic life signs can be distinguished from those of normal humans." He didn't add or whether demons even exist, but his face betrayed his skepticism.

"Well, we do have the sensor data from Muncie," Carter noted. "I can look over the readings for Gabriel and Kali once we get Brady delivered to the Winchesters. That would at least tell us whether any kind of supernatural creature gives a different sensor reading from humans."

Teal'c tilted his head in concession. "But did it not strike you, Col. Carter, that Dean Winchester seems to regard Brady and Crowley as two of a kind?"

Carter looked again at the white dot, which had moved to a position next to Dean's life sign. Then Marks cursed as the white dot suddenly jumped to another position away from both Winchesters.

"Holy Hannah," Carter breathed. "You're right, Teal'c. Marks—"

"On it, ma'am," Marks replied, his hands already flying over his console.

Tearing his gaze away from the dreary overcast sky, Dean slid the Asgard communication stone back into his pocket and turned to go inside, only to find Crowley standing behind him looking worried. "Thought I told you to stay inside," the hunter growled.

"You're not... bringing him here, are you?" asked the demon.

"Who?"

"Brady Williams."

Dean frowned. "Yeah, I am."

"That's a very bad idea."

"Why? Because he and Sam went to Stanford together?" Crowley blanched, but Dean didn't give him time to respond. "When were you planning to tell me about that, anyway?"

"In due time," Crowley replied, clearly trying to regain his equilibrium. "But it's worse than you think. Brady wasn't just Sam's best friend at Stanford. It was after he was possessed that he..." He glanced over his shoulder and lowered his voice. "He introduced Sam to Jess at Azazel's order. And he's the one that killed her. So we really can't bring Brady here. Sam will kill him before we get what we need."

Dean might well have torn Crowley to shreds then and there had Dishon not nudged him and said, Let me handle this.

Dean sighed. Fine. Just remember we're on the clock. And he stepped back.

Dishon deliberately made Dean's eyes flash when he brought his head up, and this time Crowley did jump. "Do not be a fool, demon," the Tok'ra snarled. "My brothers are trustworthy."

"Brothers?" Crowley echoed incredulously.

Dishon smirked. "If you are entitled to your secrets, then so am I to mine. Come. We have..." He made a show of checking Dean's watch. "Nine minutes before the shol'vah and the prisoner arrive."

Crowley made a small strangled noise and vanished. Dishon returned control to Dean, who smiled to himself, grabbed a can of spray paint and a coil of rope out of the trunk, and headed inside to prepare an interrogation room in the abandoned house Crowley had claimed for his own use.

"Need help, Dean?" Sam called from the living room.

"Yeah. Grab a broom and come sweep this floor, will you?" Dean made sure the middle of the sparsely-furnished dining room was clear, then set about testing dining chairs to find one strong enough to hold Brady.

Sam dutifully fetched the broom from the kitchen. "Where's Crowley?"

A crash from upstairs answered the question.

"I believe he fears me," Dishon said with a wink.

As the Tok'ra gave back control, Sam chuckled and made short work of sweeping a clear space for Dean to paint a devil's trap on the floor. Dean was just about to close the trap when Crowley teleported to the edge of the room, looking highly annoyed.

"You might have warned a chap," the demon groused. "You nearly trapped me."

"What were you doing upstairs, Mr. Know-It-All?" Dean shot back without looking up as he finished his work.

"Making some last-minute preparations, since you stupidly insist on bringing our prisoner here."

Sam frowned. "What's wrong with bringing him here?"

"Nothing," Dean replied firmly, glaring at Crowley briefly. "I'll explain once Murray gets here. I trust you. I just need you focused and on mission."

Catching the significance of Dean's use of Teal'c's cover identity, Sam inclined his head in agreement. "Yeah. Okay."

Dean checked his watch. "Be right back. I gotta go meet Murray. Wait here, Sam." Palming the communication stone, he stepped outside and made his way to the spot where he'd last been standing to talk to Carter. "Winchester to Hammond," he said once the stone was activated. "We're ready."

"Understood," Carter replied. "Stand by."

As Dean returned the stone to his pocket, Teal'c, wearing his favorite fedora, beamed down with a stunned Brady. No sooner had they materialized, however, than Crowley appeared behind them.

"Evening, uncle!" the crossroads demon cried, threw a burlap bag decorated with a devil's trap over Brady's head, and proceeded to bash the taller demon's skull with a crowbar.

The first blow connected with a sickening crack, and blood began to soak through the bag. Exorcism could not save Sam's friend now, Dean knew. But the second blow never fell. Crowley's arm was caught mid-swing in the powerful grip of the Jaffa.

"That was unnecessary," Teal'c stated, forcing Crowley to lower his arm away from Brady's head. "He was already subdued."

Crowley shrugged, thoroughly unrepentant. "I'm a demon, mate. Gotta let me have some fun."

"Crowley," Dean warned.

Crowley sighed and dropped the crowbar in favor of a pocketknife. "All right. But this part is necessary. We've got to lock our young friend in his meatsuit. No zapping off, no smoking out. It's an important piece of our bargaining strategy."

Teal'c raised a questioning eyebrow at Dean, who sighed and nodded unhappily. He then braced Brady while Crowley ripped open the younger man's shirt and used the knife to carve a sigil on his chest. The fact that it didn't bleed confirmed Dean's fear that the possessed man was already dead, despite the demon keeping his body functioning.

"Right!" Crowley said cheerfully as he wiped his knife on Brady's shirt. "Murray, is it? Bring him inside." And he turned and walked back into the house.

Again Teal'c waited for Dean. The hunter sighed again and supported the unconscious demon from the other side, and together he and Teal'c carried Brady in.

"How many times'd you have to zat him?" Dean asked quietly.

"Three," Teal'c confessed. "And even that barely stunned him."

Dean grumbled something very impolite about demons in Goa'uld. Teal'c raised an eyebrow in what was probably amusement.

Sam was waiting inside with the chair positioned in the exact center of the devil's trap and the rope ready in his hands. Dean and Teal'c set Brady none too gently in the chair, and Sam made short work of tying him up.

"Well, no sense everyone hanging about in here," Crowley observed. "He'll be out for hours, I'd wager."

Teal'c acknowledged him with a tilt of the head, then turned to Sam and Dean. "We will be needed elsewhere in less than twelve hours."

Dean nodded. "Okay, then I'm gonna try to get some sleep. Sam?"

"Yeah, I'll... sleep."

The slight hesitation over the word sleep only confused Crowley, but Dean knew what it meant. Teal'c had shown them both how to meditate—kel'no'reem, he called it—and Sam had quickly found it more restful than sleep, since it wasn't the sort of dream state Lucifer could easily invade and it gave him some time one-on-one with Salim. Dean preferred hunting down one of Dishon's memories and dreaming about it.

"I will keep watch, then," Teal'c stated.

Crowley looked annoyed at that. "Look here, Murray..."

"Crowley," Dean interrupted. "You want us, you get him. He doesn't leave until he thinks it's safe. Got it?"

Crowley huffed. "Fine. If you morons think he's worth the risk, I won't argue. Is he a hunter?"

"You could say that," Sam shrugged.

"I have spent many years destroying false gods," Teal'c stated blandly. "And I have hunted Wraith and other creatures that have threatened this planet." He paused, then added with a totally straight face, "No brag, just fact."

Dean was going to kill Bobby for introducing Teal'c to The Guns of Will Sonnett.

Sam nudged Dean's arm. "C'mon. Let's get some rest."

Dean nodded. "All right. Murray?"

"I will inform you when he wakes," Teal'c replied.

Dean nodded again and headed up the stairs, Sam two steps behind him. Once they had made their way to the bedroom, Dean turned to his brother. "So do you want to know now or when he wakes up?"

"It's someone I know, isn't it?"

"Yeah."

Sam bit his lip. "Let's make it later. Salim and I need to talk about some other stuff that came up while you were outside."

"You're sure?"

"Yeah."

"Okay." Dean sat down on the ratty old bed and took off his boots.

"Dean?"

"Yeah?"

Sam played with the handle of the demon-killing knife for a moment. "I just... thanks."

Dean wanted to ask what of the number of things that had happened that night was cause for thanks, but both he and Dishon knew he didn't need to. So instead he replied with a small smile and a "Get some rest, Sammy."

Sam smiled back and settled on the floor to kel'no'reem.