Variation on a Theme

A Criminal Minds/House, M.D. Crossover Fan Fiction

A/N: Hello readers! Just a few notes on this fic. It's an AU, which I guess goes without saying. It takes place in the fifth season universe of CM, not very long after Haley's death, and in the sixth season universe of House, shortly after House's return from Mayfield psychiatric hospital, and he is with his original team, consisting of Chase, Cameron, and Foreman. However, for the premise of this story, the Dibala case never occurred, and Chase and Cameron are still together. I know that sounds a bit convoluted, but I hope you enjoy!

Disclaimer: I don't own Criminal Minds or House, sadly.

Book 1

Chapter 1: Theme

Love love is a verb/Love is a doing word/Fearless on my breath/Gentle impulsion/Shakes me makes me lighter/Fearless on my breath ~ Teardrop by Massive Attack (House MD Theme)

Dr. Spencer Reid was not a morning person by any stretch of the imagination, and feeling ill upon first awakening did nothing to help. His stomach had been waging a minor war against him since he'd opened his eyes, and he'd felt increasingly nauseated. To remedy his morning blues he stopped by the small coffee shop he'd started frequenting a few years ago. It was just down the street from the BAU, in the small marine base town of Quantico, and he went every morning aside from the days they were out on cases. Lately in fact, he'd been going twice a day if he could, because the new barista that had started two weeks ago made the best mochas Reid had ever tasted. He was due to a briefing concerning a case in New Jersey so he hurried in to grab the treasured cup of coffee before heading into the office, after which he would likely be hopping on the jet to Princeton, NJ. He was greeted by Kelly, the extroverted, friendly cashier who always worked the weekday morning shift. She reminded him of Garcia with her bright eye shadow, quirky jewelry, and bubbly personality.

"Good morning Dr. Reid!" she chirped. "Jetting off on any top-secret adventures today?"

"Might be," responded Reid with a laugh, placing a hand on his stomach as a small wave of nausea passed through. He waved to the new barista Samuel, who had started making the usual mocha the minute he'd seen Spencer out the window. "Not really looking forward to it though. It's too cold outside for my tastes."

"That's because you're made of bone!" Kelly answered, handing him back his debit card.

"Here you go Dr. Reid," Samuel said, smiling as he handed over the enormous mocha. "Made to order with the extra shot." His eyes shone with a strange sort of admiration, Reid noticed. He couldn't have been more than 20.

"Thanks!" Reid said. "You've got a talent for making these things. Just curious, but are you a student around here?"

Samuel nodded. "I'm studying psychology at Georgetown. Got this job to make ends meet, so to speak."

"Cool," Reid replied, retrieving his sunglasses from his pocket and sliding them back on. "Good luck with your studies. I'll see you guys again when I get back. Have a good day!"

"Good luck on the case!" Kelly called out.

Reid wrapped his dark purple scarf tighter against the chill and waved in response, allowing the taste of the coffee to momentarily flood his senses.

10 minutes later Reid walked off the elevator and toward the familiar glass doors of the Behavioral Analysis Unit. When he stepped through the door however, he felt a bit dizzy and found himself losing his balance. If it hadn't been for Morgan grabbing his coffee before it went sailing through the air, a minor disaster might have occurred.

"Unsteady on your feet this morning kid?" Morgan teased, a wide grin sliding onto his face. "Good thing I was here or that precious caffeine of yours would have been all over the floor."

"Guess I'm extra un-coordinated today," Reid conceded with a shrug of his shoulders, feeling a little unnerved at his odd combination of physical ailments, but not wanting anyone to notice. "Everyone in the conference room?"

"JJ is almost ready, yeah," Morgan said, looking more serious now. "It's looking like a bad one though. Child abduction."

"Never anyone's favorite," Reid mumbled, feeling tired as he followed his friend to the conference room where everyone else was already gathered. "Male or Female?"

"9-year-old-boy," Morgan answered with an angered shake of his head. "Snatched from his own front yard. Two boys of the same age have already been killed; the unsub held each of them five days before murdering him, so that gives us…four days."

"It's actually an advantage for us though," Reid replied as they entered the conference room, pulling his weathered messenger bag from his shoulder and placing it on the table. "74% of abducted by children are killed in the first three hours, so the fact that he seems to have created a pattern that gives us more time, that's pretty rare. And since 65% of abducted children are girls, this unsub goes against the norm, which helps us narrow it down."

He smiled at Emily as he sat down next to her and waved at everyone in greeting as Hotch closed the door behind him, looking more haggard than usual. Reid found his heart very much felt like it was beating far too fast, but thought it was perhaps from having too much caffeine.

Prentiss, ever perceptive, gazed at him with a concerned expression, her brows furrowed.

"You okay?" she asked, leaning closer. "Your pupils are a little dilated…"

After his not so secret problem with Dilaudid a few years ago, it was no wonder she looked worried that he might have relapsed, but that was the last thing he wanted anyone to worry about. He'd been clean for two years, and had no intentions of going back, even if he sometimes had cravings. He knew that his behavior was a tad strange however, but he didn't want to miss going out on the case.

"I'm fine," he replied, smiling at her again. "No worries."

When the briefing was finished they had an hour until takeoff, and Reid found that Prentiss was eyeing him from her desk as she threw some things into her go-bag.

"You're not going to give up are you?" he questioned, meeting her gaze momentarily.

"Not just yet," she answered with a slight smirk, stopping what she was doing and leaning against the little wall that separated their desks. "You don't have to tell me, but I'm here if you want to talk."

Reid scratched the back of his head, pointedly not looking at Prentiss as he spoke. "I just…I've been feeling sick lately with sort of weird symptoms; nausea, raging headaches, blurry vision sometimes, and dizziness. It's been slight and intermittent until today. I just don't want…"

"Anyone worrying," she finished for him, a warm gleam of understanding in her dark eyes. "Or babying you."

"Yeah," he said with a nod, finally looking at her. "I get that it sort of comes with the territory of being the youngest and the fact that I seem to have a knack for getting into sticky situations, but I just didn't want to tell anyone unless it got out of control."

"My lips are sealed," Prentiss said, laying a fleeting hand on his shoulder.

"I figured as much," Reid answered, smiling again. "Thanks." He continued putting the books on his desk into his bag. After a few moments he froze, eyes squinted as they landed on the title.

"What?" Prentiss asked, used to this sort of behavior by now, but still mildly bewildered by it. "Something wrong?"

Reid shook his head, shoving the books inside and walking toward the doors where Hotch had just exited. "I thought of something and need to tell Hotch; we might be looking at this all wrong. We were thinking these kids didn't know the unsub, but I think they just might. See you on the plane!"

With that he was out the door after his boss, bag swinging wildly behind him.

Four days and one child miraculously rescued-despite-the-statistics later, Reid had worsened. They'd come upon the unsub mere minutes before he would have set to killing the 9-year-old boy, and Morgan had snuck up behind the middle-aged man, who it turned out was the local neighborhood mail carrier, as Hotch talked him down and freed the child. Morgan was in the process of handcuffing the unsub, now known as Carl Miller, and taking him over to the Princeton P.D. car that had just pulled up. Prentiss carried the terrified Owen James over to his waiting parents, whose faces were drawn with receding terror. Reid leaned against the black SUV, pushing his sunglasses closer to his eyes, vision so blurry it was starting to frighten him. The rapid heartbeat had returned and his head ached so badly that no amount of aspirin had done any good whatsoever. He heard JJ's voice a few feet away, coming closer.

"Spence?" she asked. "You okay?"

He didn't move from his position, but opened his eyes, unable to see her face with much clarity as though his contacts had simply ceased to function. He was feeling increasingly weak on his feet.

"Just a bad headache," he said, trying to smile. "I think I caught a bug or something. Don't worry about it."

"Are you sure?" she protested, the mother in her emerging, worry prevalent over her exhaustion. "You don't look good."

"Yeah, I," Reid began, his stomach roiling. Before he quite knew what was happening he felt his feet giving out from under him. He threw his arm out and fell against the car, sliding down slowly and thankful he had at least avoided smacking his head into anything. The bullet proof vest he had yet to take off suddenly felt unbearably hot and suffocating, and black spots played at the edges of his vision. He felt flushed and was certain he was about to vomit.

"Spence!" JJ shouted, kneeling down beside him. "What…"

"What happened?" came Rossi's urgent tone, sounding more surprised than Reid had ever heard before.

"I don't know!" JJ exclaimed, sounding slightly shrill now. "I…Spence, talk to us. What's wrong?"

Reid found he couldn't form the words he wanted, and felt himself slipping from consciousness. Frustrated, he tried to get his point across without panicking his friends.

"I…so hot…feel sick…blurred vision…"

"What's going on?" Hotch shouted, darting over to where the rest of his team was gathering.

"We need an ambulance," Rossi decided. He looked over at the Princeton police officer standing nearby. "Where is the nearest hospital?"

"Princeton-Plainsboro is three blocks down from here," he replied. "It's one of the best in the country."

"Put him in the backseat of the car," Hotch commanded. "We can turn the lights on and get him there faster than waiting for an ambulance. Prentiss, Morgan, stay here and make sure everything is settled and then meet us at the hospital. JJ, please ride in the back with Reid."

"But," Morgan started to protest, obviously wanting to go directly to the hospital, frustration etched into every line on his face.

"We've got to clear things up here," Hotch said, leaving no room for argument. "We've got to finish our job. It should only take a half an hour and then you can come meet us. That's an order."

As everyone broke away to do as they'd been told, Reid reached up and grabbed JJ's arm and she whipped around, eyes widening slightly.

"JJ, I really don't," he began, gaining the momentary strength to get a full sentence out. "I just need to rest…take some aspirin."

"Reid, shut up," she whispered, the no-nonsense tone she always used when working a case brimming, yet fear edged her eyes. No matter the situation, JJ did her best to maintain calm and keep control on the outside because it helped her do the same on the inside. But she felt her resolve cracking slightly because this was Reid, their sweet, brilliant Reid. "You're sick and we're taking you to the hospital, no arguments."

The last thing Reid remembered before giving into the darkness was being lifted up by Hotch and Rossi into the back of the SUV, JJ gently pulling off the FBI vest as the sirens wailed to life.

House heard Cuddy coming before he saw her, the sound of her high heels on the linoleum floors echoing through the hall, determined.

"House!" she called, sounding very much like a woman who wasn't in the mood to be tested. "You've been back a month and you're already ignoring my pages?"

"Thought I'd get back into the swing of things quickly," House replied, turning around to face her and leaning heavily against his cane, his last dose of ibuprofen having worn off. "What do you want, exactly? I do have soap operas to catch up on."

"I've got a case for you," she said, handing over several copies of the file, presumably to give to Foreman, Cameron, and Chase.

House took the files and flipped one open, scanning over the symptoms and looking unimpressed.

"It's only vaguely interesting," he said. "But the guys in the white coats taught me to be nicer to the people around me, so I'll take it."

Cuddy rolled her eyes, placing a hand on her hip. "Did you even read past the symptoms? He's a 28-year-old FBI agent in one of the most elite units. They were here solving that child abduction case and these symptoms came on. There's bound to be an odd explanation."

House opened the file again, scanning down further. "What the hell is a kid like that doing in the Behavioral Analysis Unit?" he asked, piercing blue eyes widening in mild surprise.

"I don't know," Cuddy answered, pushing a strand of dark curly hair behind her ear, a long-time nervous habit. "But the entire team is here, so play nice. The last thing this hospital needs is a tussle with the Federal government."

"Yes Mom," he replied, sarcasm dripping from his words. He grinned at Cuddy before turning back toward Diagnostics, where he found Chase making coffee, sunlight glinting off his wedding ring.

"Where's your better half and the dark one?" House asked as he pushed open the door, proceeding to sit down at the head of the table.

"Cameron went to that Chinese place pick up some lunch for us, and Foreman has about another fifteen minutes of clinic duty." He poured himself a cup of coffee, then picked up an empty cup and gestured at his boss, filling it up at House's nod. "New case?"

"FBI agent," House said, taking the cup of coffee Chase handed him. "With blurred vision, nausea, headaches, tachycardia, and temperature regulation problems."

Chase opened the file, sipping his coffee and reading. House mused that Chase was barely older than this new patient was when he'd first come to Princeton-Plainsboro, noting just how much had changed and yet how much had stayed the same. It never failed that Chase would hunch over to read a file rather than simply pulling the chair in further, as though he thought the words on the page would try to escape if his eyes weren't as close as possible.

"He's a bit young to be so high up in FBI, isn't he?" Chase asked, looking back up at House, a curious gleam in his blue-green eyes.

"Aren't you a little young to be married?" House countered. "What are you, like 19 now?

"Ha ha," Chase said, shaking his head, yet still chuckling softly at House's jab. He remembered how worried he'd been when he'd heard about House entering Mayfield, how disappointed both he and Cameron had been that he couldn't attend their wedding, twisted mentor that he was. "Could be some kind of pesticide poisoning. There's really no telling what kind of situations he gets into with his job."

"Most of those situations probably involve getting shot at," House countered, eyes moving to the door as Cameron entered, laden down with Chinese food. "But still, you could be on to something."

"Did someone spike your coffee?" Cameron asked, putting the two plastic bags down on the table and handing a carton of chicken fried rice over to Chase. "You're actually giving someone else's idea merit?"

"Shut it, Miss Smarty Pants," House said, reaching over for one of the plastic containers of egg drop soup. "I sometimes listen to other people's ideas. What do you think I have a team for?"

Cameron ignored him and sat down next to her husband, who was already digging into his lunch. She pulled a copy of the file over, slid on her glasses and began reading.

"An FBI agent?" she piped up, eyebrows raised. "That's one we've never seen before."

"And a prime case for House to get socked in the stomach," Foreman chimed in, coming through the door and instantly going for the Lo-mein Cameron had brought him. "Should be entertaining."

"Glad to see you missed that aspect of the job in my absence," House snarked, slurping obnoxiously at his soup while Foreman shook his head, eyes rolling.

Chase and Cameron laughed into their entrees at the age-old exchange between the two, both having missed the Diagnostics world more than they would have ever admitted.

"When you're all done stuffing your faces," House said, breaking open a fortune cookie. "Second prettiest Dr. Chase and Original recipe Dr. Chase, go get a history and get the down low on the rest of this team of agents. One of them could have it out for the youngin'. Foreman, go check out the police station downtown where they were working the case, see if there's any evidence of a carbon monoxide leak. Then we can move from there."

"We should get an echo," Foreman added. "The other symptoms are serious, but the heart is the most urgent."

"That too," House agreed. "Don't bother waiting in line for that. Just do it."

The three original ducklings rose to attend to their tasks, but before exiting Chase turned back toward his boss.

"I don't suppose there's anything I could do to stop you from using those nicknames?" he asked.

"Not a chance," House replied. "You two opened a whole new can of taunts as soon as you tied the knot. Be prepared." He smirked, draining his coffee cup. "Now scamper. Every minute counts for this kid."