This is an AU where seasons 6 and 7 of Buffy never happened. After Season 5, Xander left Sunnydale, joined the United States Air Force, and eventually ended up in Stargate Commmand. In terms of Stargate SG-1, this story obviously takes place in a later season.

BACKGROUND CHECK

Jack had a single star on each of his shoulders by the time Sergeant Harris was assigned to the SGC. Along with those stars came the responsibility of being the guy in charge of the SGC teams. So when Jack got curious about a man under his command, there weren't many limits on how far he could go to scratch that itch.

And Jack was having a hard time figuring out Sergeant Harris.

The personnel file was pretty straight-forward. Harris' full name was Alexander Lavelle Harris - although Jack had on occasion heard some of the men call him "Xander". Harris was a Staff Sergeant who had been born and raised in a podunk California coastal town called Sunnydale. He had a high-school degree, but no college. He joined the Air Force as a technician, but made the switch to para-rescueman very quickly. In terms of rank he was also a fast riser, having made E-6 in only eight years. There was a Silver Star for a rescue operation in Afghanistan, another Silver Star and a Purple Heart for another action in Iraq, and a lot of commendations that mentioned how Harris was extremely cool under fire. And while Harris' service record was good - hell, it was excellent - it wasn't exactly perfect. Jack couldn't help but smile when he read about Harris' apparent tendency to be a wise-ass. That seemed to bother some of the Harris' more up-tight superiors.

All in all, Harris looked like a good catch for the SGC, but there was something about Harris... something that didn't seem quite right. Something that Jack couldn't put his finger on. Something that decades of experience told Jack that he wouldn't find in Harris' paperwork.

So like he always did when he had a problem he couldn't quite sort out, Jack went to the people he trusted most.

"Sergeant Harris?" Sam said thoughtfully. "He's a good man. Very dependable. Maybe he jokes around too much - that's about the only problem I've noticed. I tried to talk him into getting a college degree and becoming an officer, but he didn't seem interested. I imagine he'll be a lifer NCO - and a good one."

Jack nodded his head slowly, "That's all? Nothing odd about him?"

Sam seemed like she was about to say no, but after a brief pause, she said, "We have a lot of people with previous combat experience. And from what I hear Harris saw his share in Afghanistan and the Gulf, but..."

Then Sam hesitated again. Jack noted the indecision - which was, to say the least, extremely unusual for Sam.

"And?" Jack prompted.

"There's something about how Harris reacts in combat," Sam finished slowly, obviously trying to choose her words carefully. "He's incredibly controlled and aware. It's almost... supernatural."

Tea'lc was characteristically blunt and to the point. "Sergeant Harris is an excellent warrior. I am pleased whenever he and I are assigned to the same mission."

Jack nodded, wondering how many people Tea'lc would put into that category. There probably weren't many.

"But there is one thing," Tea'lc added as a thoughtful frown came over his face.

Jack raised an eyebrow.

"He carries a wooden stake," Tea'lc finished.

Jack raised both eyebrows.

"Sergeant Harris has a sheath rigged on his equipment belt," Tea'lc continued, reacting to Jack's unasked question. "And he keeps a sharpened length of wood in it. I believe "stake" is the correct term?"

Jack nodded, "I think so."

"What is it for?" Tea'lc asked curiously. "I wondered if it might be a custom of the Tauri warriors from his homeland of California, but I've noticed that none of the other men carry such an odd weapon. And I did not wish to question Sergeant Harris any further since it might seem as if I were calling into question the ways of his people."

"Sorry, Tea'lc, but I don't know what it's for," Jack replied with a puzzled shrug. "Why don't we just let it slide for right now?"

Tea'lc nodded.

"Do you know what a Slayer is?" Daniel asked.

Jack thought about it and then answered, "A heavy metal band?"

Daniel blinked in surprise, "Not in this context. And how do you even know about metal bands?"

Jack shrugged, "I hear the men talk. It's one of the things that keeps me current and hip."

It took some effort, but Daniel let that pass and continued with what he was saying. "A Slayer is a human girl who has been imbued with supernatural powers so she can fight the forces of darkness."

Jack didn't say anything, but the look on his face suggested that he was considering hauling Daniel up to the infirmary for a full psychological evaluation.

Daniel didn't miss Jack's expression. "Look, Jack, just listen. Okay?"

"Okay," Jack agreed warily.

"The current Slayer is a young woman from California..."

Jack interrupted, "Let me guess, she and Harris know one another?"

"That's right. Back when he was in high-school, Sergeant Harris apparently became friends with the current Slayer. From what I've heard, he helped her a great deal. That sort of thing... look, Jack, I don't think I can express to you how dangerous that was for Harris. The guy went into basic training with more combat experience under his belt than the average Special Forces soldier."

"Daniel, how the hell do you know all of this?" Jack asked plaintively.

"There's an organization called 'The Watchers'. They exist to help the Slayer with her mission. Mostly they're Englishmen with an academic bent, but people from other countries are also involved. My father wasn't exactly a member, but he did advise them on archaeological affairs. I inherited a lot of his contacts in the organization - the Watchers are really big on bloodlines."

An odd look suddenly came over Jack's face, and then he exclaimed, "Oh, for crying out loud! That stake Harris carries - its for..."

"Vampires," Daniel finished for Jack.

Over the years, Jack had heard rumors about a unit buried deep in the Department of Defense that dealt with occult activities. So he put out some feelers that mentioned the Slayer and a man named Harris and eventually got a cautious reply. The subsequent exchange was hampered by the fact the nobody wanted to say anything definite about who they were and exactly what their respective organizations did to justify their budgets, but eventually a meeting was arranged.

The guy Jack finally met in a run-down bar in down-town Denver was named Riley. Neither he or Jack were in uniform, but Riley was obviously Army. And - like Jack - he had the look of a man who had seen more than his fair share of situations that had gone wrong.

"So Harris ended up in the Air Force?" Riley said slowly - as if the idea was somehow surprising.

"Yep," Jack replied. "What do you know about him?"

There was a long and awkward moment while Riley seemed to consult the bottom of his beer glass.

"You can trust him," Riley finally said.

Jack took a sip from his own beer and said, "You sure? As I understand it, you guys deal with some pretty strange things. Things that can control someone's mind. Or replace somebody with an exact double."

Riley nodded, "Yeah, that's true. But Harris was pretty close to the Slayer. And if he'd gone wrong or been replaced, she would have dealt with the situation."

"As of right now, how close are Harris and this Slayer lady?" Jack asked.

Riley shrugged, "I'm not sure. We... have reasons for not keeping close tabs on her."

Jack nodded, "Okay, but I need to talk to her."

Riley paused with his beer halfway up to his mouth. Then he put it back down on the table.

"Why?" Riley asked bluntly.

"From everything I've heard, Harris was pretty tight with this lady," Jack said. "The kind of tight you get when you've trusted someone with your life and you've done things together that other people just won't understand."

Riley nodded warily.

"So, among other things, I need to know what Harris tells her about my unit when they get together," Jack finished.

Riley seemed examine Jack's face closely. Then he said, "I can't talk you out of this, can I?"

"Nope."

Riley took a deep breath and let it out, "Okay, I'll set up a meet. But you've got to understand something - don't even think about getting tough with the lady. That would be really, really stupid."

Jack held up a hand, "I just want to talk. No rough stuff."

They met in a small town just south of Cleveland.

Jack was sitting in the local coffee-shop when the Slayer walked through the door. Jack had read the basic information on Buffy Summers - school records, taxes, brushes with the law, and so forth - but nothing had prepared him for the incongruity of actually meeting her. This person who everyone kept describing as a fantastically dangerous killing machine was a pretty blonde just barely over five foot tall.

Jack waved at Buffy to get her attention. As she sat down at Jack's table, Jack couldn't help but notice that once you got beyond the fact that she was an attractive young woman, Buffy also had the hard eyes and wary mannerisms that he normally associated with guys who wandered deep into enemy territory and did things that were theoretically outlawed by the Geneva Convention.

"Riley vouched for you and says this is about Xander," Buffy began in a very bleak tone of voice. "That means you get ten minutes."

Jack shrugged and said, "Tell me about Xander Harris."

Buffy cocked her head warily, "What do you mean?"

"Just what I said. And since I don't seem to have much time, I'd appreciate it if you didn't waste any."

That actually earned a grudging smile from Buffy. "Why are you so curious about Xander?" she asked.

"He works for me, doing something really important. Important for the country and important for the world. But he's got this weird as hell background that makes it hard to get a lock on exactly who he is. And since you know him better than anyone else, I'm hoping you can fill in the parts that I'm not sure about."

"What do you want to know?"

"Well, for one thing, everyone who knows Harris tells me to trust him. Hell, I get the impression Riley doesn't even like the guy, but he still told me to trust him. So far, I've gone along, but now I'd like some details. You know Harris better than just about anyone else - so tell me why I should trust him."

Buffy cocked her head and stared at Jack for a second. Then she said, "What do you know about me and what I do?"

"Slayer. Supernatural powers. Fighting evil."

Buffy nodded, "That's right. I do things other people can't do. Do you know what Xander is?"

Jack frowned, "According to his record, he's a damn good man."

"That's right. He's a man. A good man, but just a man. And back when I was a freshman back in high-school, he wasn't even that. He was just a nobody in a third-rate high-school that was filled with second-rate creeps who thought they were first-rate people. Then one day Xander found out what I was. And you know what? He didn't even hesitate. He jumped right in to help me. And he and a few others stayed with me while I fought vampires, demons, assorted monsters that there aren't even names for, and even a goddess. And we did that for years while the rest of Sunnydale - a town filled with people who knew they were better than a loser like Xander Harris - looked away and pretended that nothing was wrong, all the while praying that the next time the monsters came, they would take someone else."

Jack had a pretty good poker face, and at the moment he was using it. "What does he tell you about what he's doing right now?"

Buffy shrugged, "Not much. I know he's in the Air Force and he spends a lot of time out of the country. I know he does dangerous stuff. But that's about it. Actually, that's not too surprising. Xander is always talking and joking around - and because of that everyone assumes he's a blabbermouth. But that's not true. Xander's kept my secrets for a long time. He'll do the same for anyone or anything that he thinks deserves it."

Jack nodded slowly, "Okay. Then I guess I'll just have to do my best to earn his trust."

A grin briefly crossed Buffy's face and Jack felt a pang of sadness as he caught a glimpse of the girl Buffy Summers once was.

Jack and Daniel were having a cup of coffee in the base cafeteria. Jack had just got back from Cleveland.

"So what's the decision about Sergeant Harris?" Daniel asked cautiously.

Jack shrugged and said, "It looks like he knows a few tricks that could come in handy. So he stays. And I'll have a talk with him about going to OCS. We need him running a team."

Daniel nodded and picked up his coffee cup.

"One more thing," Jack said, his eyes on Daniel's face.

The coffee cup paused, halfway to Daniel's mouth.

"Does anyone else here got a background that I should know about?" Jack finished.

Daniel winced and put his cup down as Jack's blood-pressure began to rise.

"Dammit, Daniel! Now what?"

Daniel sighed and said, "There's a couple of Marines who've just been assigned. They're brothers - Sam and Dean Winchester. We... we... really should talk about them."