A/N: Welcome to the first chapter of this eventually- lengthy story! The plot will fall into place as the chapters go on!

Emily is ready to move up in the FBI, and if that means taking a shady undercover assignment designed to undermine the BAU, she'll do it without blinking. She just doesn't realize that her target, Jennifer Jareau, will become her biggest obstacle- and heartbreak.

"Agent Prentiss, do come in. And shut the door behind you."

Section Chief Strauss's commandeering voice echoed throughout her roomy office as she sat forward towards her desk, hands folded. Emily Prentiss slipped through the entrance, shutting the heavy door behind her. The room felt uncomfortable, and Emily wasn't quite sure if it was her own nerves making it so awkward, or if it was the lack of character decorating the walls. Strauss's office felt more like a waiting room than a place the Section Chief spent every day in.

"Always a pleasure, ma'm," Emily greeted blandly, reaching forward to shake her hand before taking a seat. Although she knew what this was about, it didn't make it any less nerve wracking.

"I assume you've had enough time to consider the Bureau's offer?" Strauss questioned, straightening out a pile of paperwork on her desk as she side-eyed the dark haired girl. Emily Prentiss, the file in front of her read. The special agent was only 30, but had been in the bureau for 6 years already. Her file was impressive, her work in counter-terrorism had received nothing but praise from her superiors. Loyal, they all repeated, over and over again. Determined.

Everyone who had worked with her had advised Strauss that she would be a perfect fit for the BAU. Prentiss can read anyone like the back of her hand. If there's something the Bureau needs to know, chances are she already knows it.

"I have," Emily replied, clearing her throat. A month ago, her superior at her assigned field office had pulled her aside to introduce her to none other than the chief of the Bureau's most successful team: the Behavioral Analysis Unit. When Strauss had offered Emily a position at the BAU, she had been elated. The team was so elite, she doubted she would've ever been considered; she hadn't even applied for the opening. But somehow, they'd picked her.

It wasn't until two weeks ago that Emily had been told why.

Apparently, Strauss doubted her most favorable team. The unit has gone rogue, she'd commented, with a tired sigh. She doubted Aaron Hotchner's leadership. She feared Derek Morgan was too aggressive, too angry to act rationally in the field. She felt Jason Gideon had completely checked out from the team since Elle left, and she wondered if Spencer Reid's eidetic memory might be better used somewhere else.

Her most pressing concern, however, was Jennifer Jareau.

The cases start and end with her, Strauss had explained. The young blonde media liason had a reputation for doing it all and staying until every file was cleared off her desk. She was considered by many to be the golden agent; the perfect example of a dedicated employee. But Strauss had explained that she felt Agent Jareau wasn't behaving like herself lately.

She feared that another party may be influencing her decisions; what cases she takes, and which cases she skips over. Apparently, a pattern had been noticed. The cases Agent Jareau had rejected seemed to all lead back to one group of people. A newly discovered homegrown terrorist group.

Chief Strauss had explained that Agent Jareau was not to be made aware she was under investigation. In case, of course, Strauss was wrong, and Agent Jareau's case selection had truly been an honest mistake. The Bureau had made it clear they didn't want to lose a valuable asset over an accident. That's where Emily came in.

Emily's job would be to not only work as a junior profiler, but also to profile her coworkers. Strauss wanted answers. Strauss wanted to know what was going on in all of their heads. Especially Jennifer Jareau's.

Emily would be sent in to get close to a team she hadn't met, a media liason she didn't know. And she would sabotage them.

"And do you have an answer for me?" Strauss asked calmly, interrupting Emily's internal battle. "Agent Prentiss, by accepting this promotion and joining this unit, your career would be limitless. And by accepting this... special assignment, you would be held in the highest regards from the Bureau."

Emily stared at Strauss. Stared at her roomy office, her expensive clothing, the mountain of paperwork on her desk that needed her approval. She stared at the power the woman exuded. The power she held due to how she'd risen in the ranks. The nameplate sitting on her desk that read "Section Chief".

The power Emily so badly craved. The nameplate she deserved.

"I accept your offer," Emily replied evenly, pushing away the guilty feeling that came with the acceptance of her new job. "I'd like to start as soon as possible."

A chilling smile spread over Erin Strauss's face.

"Well then, welcome to the team, SSA Prentiss."

The first day was always the hardest.

At least, that's what Emily told herself as the elevator doors opened up to reveal the legendary bullpen of the BAU. The desks seemed crowded and messy, people were scurrying back and forth around the sides of the room. They all seemed to fade into the background. Emily had her eyes on who she was really supposed to focus on.

Seated in the dead center of the large office space was an interconnecting series of desks belonging to the star profilers of the FBI. Sprawled in his office chair haphazardly was Derek Morgan, playing with a pen as he seemed to arrogantly explain something to a younger, lean man with longer brown hair who Emily recognized as Dr. Spencer Reid. Reid was leaning against Morgan's desk, accompanied by a flamboyant blonde in wedged heels that screamed "Penelope Garcia".

Emily had studied up on the entire team before her first day, of course.

As she slowly approached the desks, she saw a tall, dark haired man in a neatly pressed suit urgently approaching the bullpen. He spoke quietly to the group and they all seemed to adjust their behavior as soon as they saw him, becoming prim and proper yet again. Emily realized he must be the Unit Chief, Aaron Hotchner.

When Hotchner waved her over, Emily realized she was staring and had gotten lost in her thoughts. Swallowing the rest of her nerves away, she confidently approached the bullpen.

"You must be Agent Prentiss. I'm Unit Chief Aaron Hotchner," the man said shortly, extending a hand for her to shake. When Emily shook it, she made note of how firm and quick his grip was. He seemed confident, yet impatient. "This is the new agent I was telling you about," he explained, turning to face the rest of his team.

The muscular man- Morgan?- was the first to step forward and shake Emily's hand. "I'm Derek Morgan," he said curtly, shaking her hand in a similar manner to Hotchner. Emily guessed the two agents were a bit standoffish to how quickly her transfer had gone through. She didn't doubt them, but reminded herself she may have to try a little bit harder to get close to those two than she originally planned.

"Dr. Reid, nice to meet you," the younger guy interjected, sticking his hand out awkwardly with a dopey smile. "You know, only 10% of applicants are recruited to the FBI each year, and of those 10% most are much older than you, your file said you just turned 30," he continued, shaking her hand as he spoke. "That's impressive, especially considering that statistically-"

"Okay Reid, don't scare the new girl away just yet," the colorful blonde cut in, waddling forward in her heels to pull Emily into a hug, pushing aside the hand she'd extended to shake. "I don't do handshakes, if you're part of this team now, you should learn early on. I'm Penelope Garcia, gatekeeper of all things knowable and unknowable."

"Meaning she is our genius technical analyst," a soft, soothing voice cut in from behind the group, making Emily immediately spin around to see who had approached.

Briskly walking towards the bullpen in a tight grey sweater with dark, pressed jeans was a thin woman with long wavy blonde hair and cerulean eyes that seemed to pierce into Emily's soul.

"I'm Jennifer Jareau, media liason," the younger girl greeted, extending a pale hand for Emily to shake. Emily took her hand slowly, not expecting the suspected homegrown terrorist to look so... innocent.

"I'm Emily Prentiss," Emily replied, eyes darting to the genuine smile that graced the blonde's face as she spoke. "It's great to meet all of you, really. I'm very happy to be here."

"It's not an easy unit to get in to," Morgan commented, raising his eyebrows at Emily. She stiffened.

"But it is the most rewarding," Jennifer interjected, shooting Emily a half smile. "Morgan here is just protective of us. We're like a little family. You'll see."

"I can tell already," Emily replied honestly as she looked around the group. "I've heard amazing things about this unit."

"Your file says you worked in counterterrorism?" Hotch questioned, curiously eyeing the new agent.

"I did, six years," Emily answered, shifting her weight from side to side. She felt like she was under examination, although she knew they were just trying to get to know her. They didn't know she had something to hide. "I enjoyed it, sir. But I'm ready for the change of pace."

The media liason's phone dinged, cutting off what Hotchner was about to say. "Well, speaking of a change of pace," Jennifer sighed, holding her phone up to the group. "We'll have to continue formalities later. We just got a case."

Emily could not believe that she was currently making herself comfortable in an oversized lounge seat aboard the BAU's private jet. I could get used to this, she thought to herself as she sat her go bag down on the ground next to her, sighing with relief as she sunk into the cushy leather. In the row ahead of her were Reid and Morgan; the two seemed to be like brothers. Emily realized to gain one of their trust, she'd have to gain both.

Sitting on the couch opposite the two was Hotchner, or Hotch as he'd instructed Emily to call him. A stern look was etched on his face as he studied a piece of paperwork on the table in front of him. Part of Emily wondered if he ever smiled. He seemed all work and no play so far; very by the book. Why was Strauss doubting his leadership? Was it a lack of emotion?

"He doesn't smile much, huh?"

Emily looked up to see Jennifer scooting into the chair directly in front of her, holding two water bottles in her arms. With a comforting laugh, Emily nodded in agreement and accepted the water bottle that was handed to her.

"No, he doesn't. Thank you, you didn't have to do that."

"It's no problem. You're the ones running around in the field, working up a sweat," Jennifer joked, leaning back into the chair as she focused her attention on the brunette. "Don't let the boys intimidate you. Like I said earlier, they're very protective."

"You guys don't get a lot of strangers working this close with you, do you?" Emily questioned, surprised by how easily the blonde seemed to talk to her, confide in her. This didn't strike Emily as someone who had something to hide. Unless she was just that good at hiding it.

"We don't. We haven't had a new member in years, until now," Jennifer explained. "I think it'll be a good thing. Besides, Penelope and I were getting lonely being the only girls on the team," she teased.

"Well you seem to hold your own," Emily replied, nodding her head towards the file in JJ's lap. "They talked about you a lot back in counterterrorism. There were rumors you were going to be pulled to the State department."

The blonde seemed to stiffen up at the idea of it, and Emily automatically wondered if she'd said the wrong thing. "I like the BAU," Jennifer said steadily, her eyes darting away from Emily's. "I plan on staying put for a while."

"So do I," Emily said softly, tilting her head as she looked at the blonde. Strauss had mentioned a backstop assignment that Jareau had been assigned to a few years back. The State department had been her temporary cover. Whatever had happened on this backstop assignment, Emily could tell that Jennifer wasn't completely comfortable with it. Emily knew she'd have to dig into the file more. She made a mental note to look into it that evening when she was away from the watchful eyes of her new partners.

I would like an update by tomorrow morning of your first impressions. Remember to trust your gut, read the email Emily opened from none other than Section Chief Strauss.

Emily sighed, leaning back against the headboard of the hotel room's large bed, letting the stress of the day wash over her. She was finally alone in her hotel room. The rest of the team, now including her, were all staying overnight in Omaha while they worked on an active serial case. Although they'd constructed a working profile- something Emily found incredibly interesting- they hadn't come any further in identifying the unsub, and Hotch had ordered them to get some rest.

All it did was give Emily time to do more digging.

In a different software program, Emily typed in Jennifer's full name, pressing "Enter" to bring up the case files attached to her profile. Strauss had allowed a special level of clearance for Emily since she was going to need to do extensive research on each one of her team members. Emily planned on using this to her advantage.

After a few minutes of digging, Emily was able to locate the file regarding Jennifer's backstop. It looked like she'd really been stationed as a liaison at an army base- negotiating with hostages. Emily frowned as she began combing through surveillance images of the case.

Most of them were just of Jennifer from a distance as she worked, standing outside a tent talking to the men, inside the camp in the operations room, and outside the tanks, sweaty, with her hair braided and messy. Emily scrolled through them, waiting to find something that stood out. Think like a profiler, she reminded herself, eyebrows furrowing.

One of the pictures made Emily stop and zoom in.

Jennifer was standing next to another girl who looked to be about the same age, wearing tactical gear and combat boots. She had a gun holstered on her hip, and Emily had to admit, the mystery girl and Emily shared a striking resemblance. Jennifer's hand was on her shoulder in a comforting gesture, and Jennifer's face was scrunched up with worry lines. The way the two were standing and the look they shared was unsettling. Emily felt like she was invading an intimate moment.

After that moment, the girl didn't show up in any other photo in the file.

Emily couldn't help but wonder what her story was. Whatever it was, Jennifer had seemed very interested in it. Had seemed interested in her.

For some reason, the picture, the caring look in Jennifer's eyes, nagged at Emily all night.