He couldn't make himself stop.

He, Dr. Spencer Reid, who held two bachelor's degrees in Psychology and Sociology and three PhDs in Mathematics, Chemistry, and Engineering, who worked at the Behavioral Analysis Unit of the FBI and witnessed sexual deviance on a daily basis, couldn't make himself stop.

Because it wasn't the prostitutes he wanted. It was her.

And every time she stood a little too closely and he breathed in her cinnamon scent, every time he watched her raven hair fall down into her face when she fell asleep on the plane, every time she stared at him - stared through him, it seemed - with those coal-black eyes, he felt his pants tighten and knew he had to have her.

He had to have Emily Prentiss.

But he couldn't have her. He would never have her. And that was the part that made his heart ache with desire instead of his groin.

During work, he'd sneak onto his iPhone and start looking at craigslist, clicking on link after link in a desperate search to find the one who looked most like her.

It made it easier to get through the day, knowing that he'd arrive at his apartment, take a shower, and answer the door to a similar long-lashed brunette who didn't mind if he called her "Emily" and who called him by his first name, which he treasured each time the real Emily did.

There was never much time for talking, though, and that's how he preferred it. It preserved the fantasy. After opening the door, he'd pay in advance and lead her to the bedroom without any small talk, envisioning himself as the kind of cool, confident man that Emily would want - instead of the nerdy boy genius she saw as just another member of her BAU family.

He never kissed them on the mouth. After hours and hours of learning the intricacies of Emily's lips, he intuitively knew that kissing the mouth of another woman would only ruin the fantasy.

He knew, for example, precisely how she'd gently bite her lip when she was thinking and how she'd bite down hard on her lower lip when she was trying to suppress her emotional reaction to a case. He knew how the right side of her lips would turn slightly upward into a smirk when they were all joking around. He knew how her full lips would pout with the corners downward when she was unhappy with herself and how she'd pout more deeply and evenly when she was concerned about someone on the team or about a potential victim.

Dr. Spencer Reid also knew that he spent far too much time thinking about his colleague's mouth.

When he was with the prostitutes, he didn't bother with foreplay. Because he'd never been with a woman he hadn't paid for, he considered foreplay something sacred, something to be shared between lovers, and these women weren't his lovers. They were substitutes. They were a means of release. They were the reason he could go to work every day and not need to excuse himself to the bathroom to quickly stroke his hard cock and come, groaning, into the toilet within seconds.

For a while, after his mild crush on Emily had turned into hopeless infatuation, that had been enough. Until the day his boss, SSA Aaron Hotchner, had walked into the bathroom at the very time his knees were beginning to buckle and he could feel his orgasm building in the depths of his groin, only seconds before reaching the point of no return. Terrified that Hotch would think it was one of the cases and not one of the agents resulting in his uncontrollable need for sexual release, that was the day Reid vowed never to give into his impulses at work again. That was also the day he sought out a prostitute's services for the very first time.

That day was nearly four years ago.

He justified it in part because it never interfered with his work. It never interfered with his life at all, really, and it took far more time to find a woman who looked enough like Emily to excite him than it did to actually engage in the act. itself. Which might have been why Dr. Spencer Reid kept a secret folder containing all of the craigslist postings and photographs of the women he'd hired, never using the same escort more than once. Release was not the same as relief, after all, and there was no relieving his unrequited love for Emily Prentiss.

Even during the act, he'd purposefully squint, distorting the woman's image so she could pass for Emily. He would tell her to take off her clothes as he awkwardly disrobed, his cock already hard and straining against his underwear. After rolling on a condom, he'd climb on top and push himself inside of her, alternately opening and closing his eyes to try and blur his mental image of Emily with the image of the brunette underneath him and thrust his hips deeply and rapidly until he felt his balls draw up underneath him and his cock throb over and over again as he came in spurts, crying out Emily's name.

Afterward, he always felt profound shame and would show the woman to the door without meeting her eyes. He always promised himself that this was the last time, that he'd never do it again.

He always knew it was a lie.

This time, though, he was really trying - channeling all of his energy into attempts to solve decades-old mathematical proofs and reading rare graphic novels about the War on Gaza during his down time, murmuring vague and distracted "mmm-hmm"s when his fellow agent Derek Morgan tousled his hair and asked in that smoothly confident voice, "What's up, pretty boy?" or when their Technical Analyst Penelope Garcia came bopping into the bullpen, green and pink feathers woven into her bleached blond hair, and cheerfully inquired, "How goes thee, my boy genius?" or even when their Correspondence Coordinator Jennifer (JJ) Jareau stared him down with those deep ocean-blue eyes of hers and mentioned how her son, Henry, had missed spending time with his Godfather Spencer Reid.

This avoidance tactic was working surprisingly well - even if he could feel the stares of his boss Aaron Hotchner and his fellow Agent David Rossi emanating from Hotch's office straight into the back of his skull as they speculated about the reason for his bizarre, withdrawn behavior and discussed how - and whether -to address it. They probably thought he'd relapsed on Dilaudid. Yes, Reid reasoned, he could most likely be expecting a drug test within the next few weeks. He wasn't bothered by the idea. Hopeless infatuation couldn't be detected through a urine toxicology screening, and that was the only addiction he'd managed to succumb to since he'd stopped injecting opiates.

But then after a few weeks passed with no prostitutes and with sufficient relief from his morning and evening jerking off rituals, Emily came to work wearing that shirt. A sweater, to be precise. Red. No, more like crimson. Tight across her bust, showing off the outline of her pert, beautifully full breasts. Short above the stomach, revealing a hint of her tight creamy flesh whenever she reached up for something and the rise of a lacy black g-string underneath her low-rise pressed pants every time she bent forward.

From the moment he'd glanced up at her from his desk and felt all of the saliva in his mouth suddenly disappear, Dr. Spencer Reid knew that today was going to be a very, very hard day indeed.

In more ways than one.

After the team had gathered in the briefing room, Agent Hotchner began to present the current case. "There's been a string of prostitutes murdered in the Washington DC area," he informed them in his typically dispassionate, authoritative tone. "All of the women have one thing in common: they were using craigslist to promote their escorting services."

Reid felt his vision blur and his throat become dry. With a shaking hand, he reached for the cup of coffee in front of him, wincing as it burned the back of his throat.

"In your folders, you'll find the last known postings by the missing women. There seem to be 22 in all, spanning a period of six months. Fourteen bodies discovered throughout Virginia have already been matched to familial DNA in the missing persons database. And the most recent victim was reported missing yesterday so we'll be operating under the assumption that she's still alive."

Agent Rossi, steady and measured as always, added, "Since the unsub used craigslist rather than street hookers and we've already confirmed that phone contact was made prior to each meeting using a disposable cell phone, this unsub probably comes across as non-threatening to women in his everyday life. He most likely holds a steady job and lives in a middle-class or affluent neighborhood since the women he hired were comfortable enough to arrange meetings with him at his house or apartment. His sexual awkwardness or inexperience may also factor into those conversations and meetings, lulling his victims into a false sense of security. Someone overly charming or confident would have been unlikely to gain their trust so easily. It's even possible that he has never had sexual intercourse without paying for it."

As JJ passed out folders to the team members, Reid was stunned into silence listening to a profile that could have described him perfectly. When he received his folder, he flipped through each page hurriedly and was relieved to discover that they were all blondes. Still, he couldn't help the choked panic and guilt rising in his chest as he stared at the photographs of the women, before and after they were murdered.

JJ's blue eyes surveyed the team as she noted, "this only became a BAU case because the family of the most recent victim contacted the media, so there's pressure from above to solve this case and to solve it quickly. Until now, no one has connected the murders or the disappearances and everyone is demanding to know why."

"I don't get it," Emily murmured.

"Don't get what?" Derek asked. "Why 22 women disappeared before we were notified?"

"No, no," Emily replied, shaking her hand dismissively. "We all know that prostitutes are the easiest targets for serial rapists and murderers because their disappearances are rarely taken seriously by local authorities. What I don't get is why a man would hire a hooker in the first place. Why not just go to a bar and have a one-night stand for free?"

"Because it's not just about sex," Reid muttered to himself.

Realizing that he had spoken aloud and that the team was now staring at him, awaiting further explanation, he looked up and met Emily's dark brown eyes, trying to hold her gaze instead of letting it fall down to where her crossed arms had given him a spectacular view of the black lace bra peeking out from under that red sweater. Speaking exclusively to her, as close to a confession as he thought he'd ever come, he continued. "The unsub obviously has a type. Blonde hair, green eyes, early twenties. There has to be someone in his life who matches that description, someone he's desperately in love with but knows he'll never be able to possess. He hires escorts specifically because he doesn't have to talk to them or get to know them. It would ruin the fantasy. He's not looking for a relationship. He's not even looking for sex. He's looking for ..."

"... a substitute." Agent Rossi finished just as Reid's voice quavered and began to falter.

"So why kill them?" Morgan ventured, interlocking his fingers behind his bald black head. "Why not just use 'em and lose 'em?"

For a moment, Reid simmered with pure vitriolic hatred for his colleague. Use 'em and lose 'em? He wanted to stand up and demand to know how Derek Morgan could live with himself after sweet-talking his way into girls' panties, leaving them the next day without feeling any remorse about all the promises he'd made before screwing them senseless. That was far closer to 'use 'em and lose 'em,' wasn't it?

And then it dawned on him. "I've got it." Reid stood up as the words poured out of him in an excited torrent. "OK, guys, think about it: what would most men feel after paying for sex?"

"Uh, stupid?" Emily spat out, her sarcasm cutting him to the core.

Morgan shrugged, like the idea of paying for sex was as foreign to him as the idea of learning Quantum Physics.

JJ chewed on her lip. "Remorse, maybe?"

"Yes! Good!" Reid shouted, writing the word on the white board in a blue dry-erase marker.

"Shame," Hotch added. Reid nodded enthusiastically and wrote that word on the board, too.

"Extreme self-hatred," Rossi contributed.

"Yes!" Reid responded emphatically, writing "self-hatred" on the board and then circling the word "self" three times. "We have an unsub who chokes these women so violently that he often breaks their windpipes. He feels hatred but it's not himself that he hates."

"So it's the hookers? For not ... living up to the fantasy?" JJ speculated, pushing a blonde strand of hair out of her face.

"No, no ..." Rossi shook his head. "Traces of the same person's semen were found inside all of the victims. He would have become impotent if they hadn't at least fulfilled that part of his fantasy."

After a pause, Emily spoke up. "It's the woman he hates. The object of his obsession? Sheis the source of his rage."

Hotch cocked his head, a frown on his weathered face. "How so?"

"Well," Emily continued, looking around the table to gauge the team's reaction, "if this unsub is socially awkward and sexually inexperienced, maybe he tried to act on his feelings but he was rejected - rejected to the point of humiliation. He still desires her but he also hates her. It's not the prostitutes he wants to kill. It's her. In fact, I bet he's been using prostitutes for as long as he's been obsessed with her. But the trigger that led him to start killing them? It had to be rejection."

"Love and rage ..." Rossi murmured. "Sounds like we've got a profile."

Reid sat down, feeling weak and nauseated. If he ever worked up the courage to ask Emily out and she rejected him or humiliated him, would he hate her? Or would it be like the everyday embarrassments he endured when the team teased him about his lack of experience with women? On the other hand, if he never acted on his feelings, how much longer would he be tormented by them? Would they ever go away? And was this even real? Was this love or was it just some kind of sick pathological obsession?

At around eleven p.m. - just when conflicts about the profile were beginning to break out between the team and Garcia had managed to link several phone numbers on the missing women's cell phones to some extremely high-profile politicians, prompting a warning from their Administrative Director Strauss to "proceed with extreme caution" - Hotch told everyone to go home. "And that's an order," he added.

When JJ pointed out timidly that a woman was still missing, Hotch shook his head firmly, insisting that a good night's sleep would provide them with fresh eyes tomorrow. "Bring the case files home, examine what we know, and try to imagine yourselves in this situation. Morgan, Rossi, Reid: imagine you've hired an escort to come to your apartment. Prentiss and JJ: imagine you're an escort preparing to meet a new customer at his apartment. The key here is trying to understand the behavior of the unsub before he started killing. Now go home and prepare to report back tomorrow."

Sitting in his apartment thirty minutes after leaving FBI headquarters, Reid dropped the case file on the kitchen table and poured himself another cup of coffee, not planning on sleeping tonight. After all, he didn't have to imagine what it would be like to hire an escort. He already knew. The only way he could ever view this case with "fresh eyes" would be if Hotch personally severed the connection between his ocular nerves and his frontal cortex.

Besides, Spencer had memorized the entire contents of the file within the first five minutes of receiving it. Bringing it home with him was really only an attempt to dodge further comments from the team about his eidetic memory. Sometimes the BAU felt just like being back in high school, where his genius mind had been the subject of ridicule and social isolation.

Ignoring the FBI file, Reid side-stepped the couch and the countless dusty stacks of first-edition British literary classics to open the third drawer of his mahogany computer desk and examine his own personal "case file" - a record of every escort he'd hired in the last four years.

The effect of his magician-quick hands flipping through the pages permitted Reid a millisecond glimpse of each photograph, the features of the individual women combining so rapidly in his subconscious that the illusion resulted in a nearly-perfect composite sketch of Emily. He closed his eyes and conjured up memories and sensory details of the past twelve hours: the soft touch of Emily's hand on his shoulder and the dampness of her bitten cuticles brushing his neck when she'd asked him if he was OK for the third time that day, the violet cinnamon scent of her hair he'd inhaled deeply into his nostrils when she'd reached over him to grab the Splenda for her coffee, the tantalizing glimpse down her shirt and the view of her full perfect breasts covered by only that thin sheen of black lace when they'd simultaneously reached under the desk for a dropped piece of paper ... Although he'd managed to hide and suppress his arousal at work, Spencer Reid's cock now strained against his pants, throbbing so hard and so painfully he knew it would only take a few strokes before he exploded, spurting and shuddering and moaning her name.

And then he'd do it again. And again. And maybe even once more after that. As many times as it took until he could fall asleep, spent, holding his pillow against his chest and pretending it was her.

Just as he began to lower his zipper, whimpering as his hand brushed over the fabric of his corduroy pants, there was a knock at the door. Then three successive, sharp knocks.

Fuck, Reid thought. Fuckity-fuck-fuck-fuck. Glancing at the clock, he noticed that it was fifteen minutes after midnight. And that knock ... he knew that knock. It was a police knock. An FBI knock. Oh god. A knock like that at this hour couldn't mean good news.

Reid was already beginning to lose his hard-on as he made his way to the door and stammered, "Who - who is it?"

"It's Emily," the voice on the other side of the door responded. Between the shock of hearing her voice and the flatness of her affect, Reid's dwindling lust was transformed into profound concern.

Sweat gathered on his forehead as he fumbled with the locks and swung open the door, intense worry reflected in his deep-set eyes and the only important question at the moment - "are you OK?" - beginning to form on his lips.

Before he had the chance to ask, though, Emily grabbed his tie, a sultry pout on her lipstick-red mouth, and drew his body so close to hers that he could feel her curves against his quickly-recovering erection as she purred in his ear, "Hey, baby. You lookin' for a date?"

And then she stepped back, collapsing in a fit of laughter.

By the time she looked up again, Spencer was no longer standing in front of her but storming through his apartment and into the bathroom.

As he slammed the door behind him, sinking down onto the cold tile, he tried not to hyperventilate. Remembering his mother's panic attacks. Remembering what he used to tell her when she couldn't breathe, when her hands wouldn't stop shaking, when she said the whole world was spinning and there was nothing solid to hold onto. If Spencer Reid had never entirely understood what his mother had meant when she cried and screamed that there was nothing to hold onto, he definitely understood now.

Emily cautiously closed the door behind her and walked through the apartment, following his path and crouching down next to the closed door. "Reid?" she murmured, genuine concern in her voice. "Spencer? ... I was just kidding. Remember what Hotch said before we left? About imagining ourselves as escorts and johns? I - I thought it would be funny."

Spencer clenched his fists so tightly against his knees that they turned white. "What, so you decided to act it out using a - what did Hotch say? - a 'socially awkward and sexually inexperienced' guy who could only ever get a beautiful woman by paying her? You thought it would be funny? Well, Emily, I guess I just don't understand your idea of humor," he snapped bitterly. Emily had never heard his voice so wounded, so hurt. She'd witnessed him choke back tears on more than one occasion, but not like this, never like this.

More than that, the content of his words shocked her to the core. Sure, maybe he was sexually inexperienced but didn't he at least know that some women found it far more erotic to teach than to be dominated? With that brain of his, hadn't he ever realized that this was, in fact, why she treated Morgan so coolly when he tried to entice her with flirtations and innuendos? Couldn't he tell that the idea of submission didn't excite her in the least and that she lusted after someone for whom every touch, every lick, every stroke was new and arousing and controlled by her?

And ... had Spencer Reid just called her beautiful?

In an uncharacteristically quiet and reserved tone, Emily said, "I actually came here to borrow your case file. I accidentally left mine at the office and since you don't need it to remember the details, I thought that maybe I could borrow yours?" When she was met with stoic silence, Emily stood up. "Never mind. It was a stupid idea. I'll just go back to the office and catch a few hours of sleep there." She paused. "And Spencer? I'm so sorry. I had no idea you thought I saw you that way. I don't, you know. I never have." Another awkward pause. "Well, I guess I'll be leaving, then ..."

"The table." A monotone voice spoke from behind the door.

"Thanks, Spence," Emily intoned gratefully, looking around the living room before seeing the brown folder with the FBI logo. He could hear the click of her black boots retreating from the bathroom door as she called out, "I'm just going to flip through it on the desk for few minutes and then I'll be gone, OK?"

The desk.

Panic seized Reid as he pushed open the bathroom door and shouted, "No, Emily -" but it was too late. She'd already opened the folder and started paging through image after image from craigslist's erotic services of women who all looked like her. When she finally registered his presence, she stared up at him in open-mouthed shock.

Spencer Reid, for once in his life, found himself incapable of speech.

Emily closed the folder and sat down on his couch, her expression dazed and disbelieving, her eyes flicking back and forth as she tried to make sense of what she had seen. Finally, she looked up at him and said evenly, "Reid, sit down. I think I deserve an explanation."