Hi everyone!

As mentioned in the summary, this is the sequel to Someone Who Understands where Charlie Eppes and Spencer Reid meet and have their first date. Then I heard a song on the radio (Incomplete by the Backstreet Boys, if you must now... =P And no, I never liked them.), and it inspired me to write another story about what happened after that night. I decided to make it a new story so that I could adapt the rating.

Again, I'm not good at maths and made up all the math-related talk, do not take it seriously! Really, IT IS ALL COMPLETE BOLLOCKS!

I don't own any of the characters, they belong to those who invented them in the first place.

Spencer stared at the screen of his computer and tried to focus. It was late and he was the only one left in the office. He felt exhausted and there was a headache beginning to form behind his eyes. But he was in the middle of filling out a report and really needed this done before he went home, he couldn't just leave it.

Weapon(s) used: 'Hatchet', he typed, 'brand: Bechstein, blade made of steel, 5.67 inches, handle made of walnut wood, 16 inches, with traces of blood from the victim.' Scene of crime: '49 Ivy Street, Montebello, Los Angeles.' LA. That's 3677.886 kilometres or 2285.4383604 miles from here, linear distance. There was an unpleasant feeling in Spencer's chest, like a ball of hurtful, fierce, acid fire that made it difficult to breathe. He swallowed but it didn't go away. Motive: -

"Hey kid, still here?"

He looked up and saw Morgan standing on the right side of his table clutching his bag.

"Um, yeah. I've got to finish this."

Morgan leaned closer and read the name of the case. "Henry Guess? Didn't you start filling that in half an hour ago? You still not finished that?"

"Yeah, I'm quite tired and got distracted..."

"Well, something seems to be on your mind indeed! You've been typing very slowly when I came into the bullpen."

Spencer just nodded but didn't want to elaborate on his thoughts, or feelings for that matter. If he could just finish this report and go home...

"In fact, you've been distracted since we're back from LA three days ago." Morgan raised an eyebrow. "You know that Garcia told me that on our last evening you had a date, and you never want to talk about it-"

"That's not even true!", he interrupted angrily. He was so incredibly tired of his teammates' teasing about this! "Why does everyone think I was on a date? I was just having a cup of coffee with a maths professor-"

"So was she nice?", Morgan grinned.

"Yes, he was nice!"

That answer had the desired effect. "Oh! He... Sorry, I-"

"Garcia wouldn't listen, I told her that I was drinking coffee with someone and she just assumed it was a date! And she even had to tell all of you!", Spencer ranted.

"Well... you must admit that it's rare that you talk to people."

Spencer frowned in incomprehension at the other man.

"Except us, I mean. Or when it's case-related.", Morgan added. "I guess she just hoped it was a date."

"We were talking about how to theoretically build a quantum displacement link. Professor Eppes managed to include light velocity into the famous Flecknoe Formula." He tried not to think about the look on Charlie's face when he had exclaimed I've got it!, or what they had been doing at that precise moment. Well, trying not to think about something makes you think of it, and Spencer miserably failed. His face burned and he hoped his friend wasn't looking at him too closely, he would surely notice him blushing. "Er... We used a detour through geometry and therefore we were able to explain the irregularities-"

"Um, I really need to go now!"

"Oh, but this is fascinating! I don't think anyone else has done this before!"

"Yeah... sounds like you had a great time. Sorry, but I've gotta dash, really!"

"Okay, see you tomorrow!", he called after Morgan. As he saw his teammate scurry out of the room he smiled to himself. His little plan had worked, he was alone again.

Alone with the Henry Guess-case and this very uncomfortable feeling inside him. His cheerful mood was damped by this thought, and he turned back to the screen. Motive:, he read. 'Jealousy', he typed. Numerous pictures of Charlie flashed in and out his mind, him smiling, him looking into his eyes. Not now, he thought, just one more point to go! Suddenly there was a vivid memory of how Charlie's hair had felt, how his neck had smelt... and tasted. He sighed and put his hands over his face. He shouldn't be thinking of that. All of a sudden it was hard to breathe and he had to blink away tears. He tried to focus on his report again. Summary of accomplishment of case: The bright, fierce light of the screen made him feel headachy.

No, Spencer decided, this would have to wait for tomorrow. He just didn't have the nerve to complete the file right now. With a heavy sigh he got up and collected this things in his brown leather bag.

Why didn't he stay? It was the question he had asked himself a hundred times every day since he was back from Los Angeles. He had thought that there was a unique connection between him and Charlie, that they understood each other like no other person ever had. But apparently Charlie knew someone else like this, or he didn't really care about it. Why else had he left in the morning while he, Spencer, had still been asleep, without leaving any message? Wasn't this a sure sign that he didn't want any more contact? He couldn't be entirely sure of this, there was always the possibility that there was another reason for Charlie's leaving. But this, love, or one night stands, or whatever it had been, was an entirely unknown field to him and he didn't know the odds for his friend's behaviour at all. All he knew was that only 2% of one night stands ended with the participants having a relationship afterwards. Le Monde, 04/09/98; page 47, an article called 'L'aventure d'un soir'. Not very promising...

He walked slowly towards the entrance of the BAU headquarters. The shockingly cool air outside was somehow soothing. He realised he had forgotten to bring a jacket with him in the morning, now he was freezing in his sweater. Spencer didn't really care, the physical discomfort distracted him from the pain in his heart. He walked to the bus station and patiently waited. The air he breathed out formed little clouds in front of his face. As he waited he tried to divert himself with thinking about exactly why string theory was not plausible. It wasn't very entertaining since he knew the answers and couldn't find any new ones. When the bus finally came he was still busy finding an alternative to string theory, something that did successfully link quantum and relativity theory. He was not disappointed to arrive at home without having found a solution. Apparently it was not the time for a shift in his paradigms right now.

Spencer cooked himself pasta with tomato sauce and ate his dinner while reading an article on new insights about gardening in medieval England. The headache was still there, though, and he felt that reading wasn't the best occupation for him right now. He took an aspirin and decided to call it a day and try to sleep.

Two hours later the physical pain had faded away but he still lay wide awake, staring at the ceiling, wondering whether the heartache would ever go away. It had on previous occasions but none of these occasions had included someone he cared for that much. Only thirty seven minutes of talking to Charlie Eppes had been enough for him to realise he'd found a soulmate. But it seemed that the latter did not feel the same way and Spencer was profoundly convinced that he'd never felt such a grade of misery before because of this.

Yet he couldn't help recalling the events of their one and only evening together. How Charlie's mouth had tasted of chocolate chip muffins and caffè latte with an extra shot of espresso at their first kiss. How shyly Charlie had smiled at him afterwards. How they had spent the remaining time till dinner aimlessly walking through Los Angeles, talking about Star Trek while occasionally exchanging bashful glances. Had Charlie really not at one single moment felt that there were sparks flying between them? But oh, the way he had flirted with him during dinner! And god, on their way back to the hotel he'd suddenly dragged him into a dark alley and had started kissing him again. He'd tasted of chips and sweet wine and manliness, and Spencer had loved the whole situation. The abruptness, the secretiveness, the determination of Charlie's tongue, the hard, rugged and dirty wall he felt behind his head and back, the warmth of the other man's chest against his, and the wildness of his hands all over his body.

Even the thought of it all turned him on now, though it also thrusted the arrows of pain deeper into his heart. He decided to try and recall every detail of the evening and then decide whether there had been any sign of Charlie loving him. And if he found only one he'd call him the next day. After figuring out his number, obviously...

He remembered vividly how he'd whispered in Charlie's ear that he wanted them to go to his hotel room, and he had felt the other man breathe heavy into his own ear, hot lips caressing his skin, as he had answered, "Yeah, we really should discuss that quantum link theory in private..."

He had taken Charlie by the shoulders and turned him around, so that he had now been the one pressing the other against the brick wall, and had looked him directly into his brown eyes, their faces only inches apart. "Actually I had something else on my mind." He had fiercely kissed his lover and their noses had brushed against each other before he had explained, "I thought about conducting some experiments."

Charlie had leaned forward for another kiss, and as Spencer had wanted to draw back he had gently bit him in the lower lip. He had whined into their kiss, and they had become entangled into a battle for dominance, staggering deeper into the dark alley. Finally, he had Charlie pinned against the cold wall again, and had felt surprised to feel the other's hand wander down his back and firmly grip his bottom.

"Chemistry experiments?", Charlie had asked.

Spencer had shook his head. "No, the chemicals between us seem to be all right." Charlie had smiled coyly at this. "I was thinking about biology."

While the other man had nibbled on his earlobe he had answered, "Let's go then, and carry out your experiments, doctor!"

They had eventually managed to tear themselves away from their embrace and started walking again, silently this time, the promise of sex lingering in the air. Spencer had only let go of Charlie's hand as they had arrived in the vicinity of the hotel. He hadn't been quite sure whether he wanted any of his colleagues to see him like this.

The moment the door to his room had clicked shut he had been all over Charlie again, kissing him with a force that spoke of his burning ardour, ripping open his shirt, pushing him towards the bed and on his back. His cheek had gently touched the other man's chest, and his lips had wandered from one nipple to the other. For a while Charlie had laid still, enjoying the caressing, but soon it hadn't been enough for him, he had started to tear at Spencer's shirt, trying to get it off him. Spencer's lips had continued kissing the other's chest, but they had moved upwards, towards the delicate skin of the throat. This was when Charlie had managed to wrench the shirt open with force and he had pushed it back, revealing Spencer's shoulders. Since this had impeded his movements he had sat up, straddling on the other man, and taken it off completely, slowly, enjoying the hungry eyes that had taken in the view of his torso. Charlie had already fingered with the latch on Spencer's belt as he put his hands on either side of the young man's head and hovered above him. He remembered the brown eyes that had been fixed on his crotch before and then they had looked up and squarely into his own eyes. He had swallowed. Charlie had used the moment to push him on his back and roll on him, his bodyweight pressing him against the sheets, kissing him passionately. The young man had propped himself up on his elbows to be able to get into a more comfortable position, but his whole body had still laid on Spencer, making him unable to move. Not that he had wanted to move. He had wanted to lie there forever, feeling Charlie's tongue in his mouth moving fervently, those beard stubbles grating his chin a little, that heavy and hot body pressing him down, those hands stroking his hair, together with the almost unbearable anticipation that had been wavering around them...

And now he wanted to be there again... How he cursed his photographic memory that made him relive all these heavenly and bittersweet details so exactly! He bit his lip as he started touching himself, picturing Charlie lying on him, just as he had that night.

He remembered how he had again fingered with his belt with one hand, still kissing him, still lying on him, and this time managing to open it. He quickly had unbuttoned and unzipped Spencer's jeans, then he had put his hand down his pants, stroking his buttock. Spencer had moaned into their kiss and had gripped Charlie firmly by the neck to push him down harder. The young man lying on him had had no difficulty removing his jeans but he had had to draw back from their kiss and sit up to take them off completely, and all the while he had been placing little kisses on Spencer's slender legs. Stripping off his lover's underwear had proved to be more complicated due to the obvious problem of the erection but Charlie had eventually coped.

Spencer had expected his lover to lay down so that he could start undressing the other man but Charlie had been faster, already pulling down his own trousers and laying on the other man again.

"Have you done this before?", Charlie had asked breathing heavily.

Spencer had shaken his head.

"We'll need lube."

He had gotten up and had rummaged in his luggage till he found what they needed.

"What position?", he had heard his lover mumble as they were laying together on the bed again, side by side, lips meeting for one eager kiss after another.

He hadn't really known what the positions were called. "I want to look at you."

Their lips collided again as Charlie's hand had gently slid down Spencer's side. Carefully he had stroked his entrance and he remembered how he had winced a little at the unusual and unexpected touch.

"You are gorgeous!", Charlie had whispered. He had felt his knees go weak and his body had relaxed a little. His lover's hand, there, felt quite nice actually. Cautiously Charlie had applied the lube and then he'd entered with one finger, slowly, carefully moving it, whispering sweet words to reassure and soothe the other. Spencer had started to moan, and Charlie had asked with a very serious expression, "Does it hurt?"

He'd shaken his head. It had been exciting and delightful. "Don't stop!"

"Shall we try then?"

Spencer nodded curtly and whined in disappointment as Charlie's finger retreated. But just a few seconds later he'd felt pushed back onto the bed, Charlie's hands pressing his legs apart, and his arousal had rubbed against the other's. He had jerked back his head and had heard the other man whimper with desire. And then Charlie had been inside him, pulling out and pushing in again very gently but Spencer had seen that he had trouble restraining himself.

"Is it still alright?", the man hovering above him had panted.

"God, yes!"

Charlie had started to move his hips a little quicker and soon they had found a steady pace, making the bedstead squeak. Both men were breathing hard and panting loudly, occasionally moaning and sighing as well, and calling out each other's names. What if his team members heard them, Spencer had thought, but not had he just not cared, he had also felt rather aroused by the thought. He had matched the movements of his hips with Charlie's thrusts.

And suddenly he had felt the passion and lust bolt through his body even more ardent. "Oh, yes, Charlie, don't stop!", he had yelled, just before an intense wave of desire had surged through him and he had spilled his semen onto both of their stomachs.

Charlie had only needed a fraction of a second longer to hit the peak, mouth and eyes wide open, calling out "I've got it!" After he had come he slowly pulled out of Spencer, then he collapsed on the bed next to him, still breathing heavily. "Geometry!", he had gasped.

"What?" He felt a sudden wave of fatigue roll through his body.

"Geometry!... If we... try to solve... the problem... by using geometry... we can... picture it... better..."

He had looked at the other man. "Oh... You want... to convert... the Heiser... Equation into... isosceles triangles?"

Charlie had nodded, brushing a sweaty curl out of his face. "And... we can use... Pythagoras... for the... nonlinear... cross-equations!"

"Wouldn't... vector algebra... work better... and make sure... you elude... getting stuck... with quantum... energy?"

The last thing he remembered before he had fallen asleep was how Charlie had turned to face him, his chest still heaving, but his eyes locking with Spencer's in awe. "That's... brilliant!"

He still didn't know what time it had been when he had awoken again. It must have been night still, because the light had been on. He had seen how Charlie had sat on the floor, wearing his boxers, and scribbling wildly away on a notepad.

"Hey, what are you doing there?", he had mumbled, supporting himself on his left elbow.

Charlie had looked up from his work, beaming. "I just figured out a Flecknoe Formula with light velocity!"

Suddenly Spencer felt wide awake. "Really?"

"Yeah, look!", he had gotten up, had gathered his notes and had laid next to Spencer. "I did what you suggested with the vector algebra and figured out that the measure we need is subadditive. Then I thought that if I use polyhedral forms instead of non-polyhedral ones I might manage to calculate the capacity of that hyperbolic function here..."

"Oh I see, and then you used binomial equations... and arranged a diffeomorphism... wow!" Spencer had felt fascinated. This was incredible!

"And look, it belongs to the orthogonal group!" He had heard Charlie's excitement in his voice. His own heartbeat had accelerated.

"Of course! Which means you could apply the cosine rule!" Spencer had gaped at the notes. He remembered how he had been utterly baffled and how his breath had quickened as well. "And then you multiplied the result with the Sigma-finite measure you figured out before and..." He just hadn't been able to get his head round the fact that someone had actually calculated all this. "Charlie, you made it!", he had added with reverence.

"Yes..." His lover had sounded like he couldn't even believe himself what he had done.

They had both looked up at the same time, realising only then that they had been lying very close to each other, their faces only an inch or less apart. As engrossed as he had been in the rearranged Flecknoe Formula, instantly he had been distracted by Charlie's closeness, and that beautiful half open, astonished mouth. As his eyes had flickered back to the other man's he saw that his attention had been equally diverted. Immediately he had leant forward to meet his lover's lips for a hard kiss and they had begun to snog passionately. Soon afterwards they had been making love again.

Later Spencer lay in bed, exhausted and crying. Somewhere while reliving all the events in LA he'd forgotten that he had wanted to look for signs that showed that Charlie was in love. All he felt now was the pain of finding himself alone in the morning. Everything had been gone, Charlie, his clothes, and the seventy four sheets containing his notes, drawings and equations. In the bin he'd found crumpled-up papers with some attempts to work out the relation of Pi and an isosceles triangle. That, and the handkerchiefs on the bedside cabinet had been all the evidence of last night. Confused and refusing to believe that his lover had really left without leaving any notice, he'd waited for Charlie till Hotch had called and asked where the hell he was because the team wanted to leave. Now the unsuccessful notes on Pi he'd smoothed and pocketed were all the proof he had that the night in LA hadn't been just a blissful dream.

Spencer's alarm roused him from his sleep and his hand clumsily found the stop button. He got up and still felt tired out. After a shower and a cup of strong tea he felt a bit more able to face going to work. As he stood in the metro reading the newspaper he realised he'd forgotten his jacket again.

He tried to engross himself in his work but unfortunately it didn't require much effort. He'd decided to finish the Henry Guess-file in the evening, after he'd done everything else, so it didn't slow him down for the rest of the day.

A few hours later had completed everything necessary except the report from their last Los Angeles-case. He was looking at his screen again but not taking in the writing on it, and wondered whether he should just try and find Charlie's number. It wouldn't be too difficult, the office number of Agent Don Eppes was still saved on his mobile phone and he'd surely know his own brother's telephone number. He glanced at the clock on his computer. LA was three hours behind, Don must still be at work. But what if Charlie had told him everything? Or was notorious for doing these kind of things? Perhaps this was his method to solving math problems? Or Don might be doing something really important and be rather annoyed about his seemingly nonrelevant call. This might turn into a rather embarrassing conversation...

He had another idea and opened the internet connection. Quickly he found the website of CalSci University and Charlie's official contact details. He didn't have to take a note of the number, he'd already memorised it. He took his phone out of his pocket and looked at it. To call or not to call: That is the question!, he thought, at the same time feeling a bit ashamed of himself for misusing the bard's quotation.

He gathered all his courage, quickly dialled the number, pressed the 'call' button and held the mobile phone to his ear. His heart was beating fast. With every signal ringing out his breath quickened. God, what am I going to say if he actually takes off the phone? He hadn't wasted a thought on this before. Shouldn't he go somewhere more private? This might also turn into an embarrassing conversation...

He flinched when someone took off the phone. "Hello, Secretariat of Professor Eppes, Petersen here, how can I help you?", a lady's friendly voice said.

Spencer gulped. He hadn't expected someone else. "Um... hello Ms Petersen, here's Dr. Reid, I'm calling from Quantico. I... um... I wondered whether I could talk to Professor Eppes."

"The professor isn't here now, I'm afraid. However, I can leave him a note if you like. Why did want to speak to him?"

"It's about his work on the quantum displacement link theory.", he answered like a shot, hoping she was not a clever student who knew that this theory didn't exist. "But perhaps it would be easier if you gave me his personal number."

"I'm afraid I can't just hand out his private contact details to strangers."

He saw how Prentiss steered towards his desk. She whispered, "You've got a visitor!", and pointed into the direction of the entrance hall.

He nodded at her and mouthed, "Thanks!" Aloud he said, "Of course I can understand that but I've been working with him on exactly this problem, he knows me."

"I don't think he ever mentioned you.", the secretary answered.

He sighed and tried to decide whether he wanted that Ms Petersen left a note for Charlie or not. He might appear desperate but maybe it was worth it? If Charlie had left for some important reason or just forgot to leave his number this might be his only chance. He was tempted to say that he worked with the FBI but knew that it was forbidden to use his influence if it wasn't case-related.

"Alright, perhaps you could just ask him to call me as soon as possible." If Charlie didn't call back now it was also a very clear message and he'd avoided an awkward discussion. At least he had tried.

Ms Petersen took his number and he said goodbye and hung up. He just wanted to start concluding that ruddy file he seemingly wasn't able to finish when he remembered what Prentiss had said. Relieved to have an excuse not to work he got up and walked towards the visitor room.

He almost fainted when he opened the door and saw Professor Charles Eppes standing at the window watching a dove that sat on the windowsill, hands tucked into his pockets. He looked up as he heard the door click shut and beamed at him. "Spencer!"

He stood in the room, gaping, and for the first time in his life his brain had stopped working. So this is how other people feel... Then he realised that Charlie being here probably meant that there was another reason for his sudden leaving in LA and started to smile back. "Charlie? Good lord, I thought..." He felt tears of relief in his eyes and couldn't speak.

Charlie scurried forwards and squeezed him tightly. "I'm so sorry!", he whispered into his ear. Spencer felt a three-day beard rub his shoulder. Charlie's hair smelt of fresh air.

After two seconds Charlie stood back a little, but still kept his arms firmly around his waist, and hastily began to explain, "I left to get us coffee and then my brother called me and said I should come straight to the office because he had a problem and when I came back you were gone and then I panicked and when I had calmed down I asked the concierge who said you'd checked out but he didn't want to give me your address and then I asked Don whether he could help me but first he didn't want to because I refused to say why I wanted your number and when I finally persuaded him I was too afraid you'd just hang up and then I decided to come straight here instead but the first flight went Wednesday evening and I wanted to be here earlier so I took the car and drove!"

Charlie looked at him with his brown eyes anxiously searching his face for a reaction. Spencer had to smile at his detailed explanation. "What? You drove all the 2678 miles over the 44 and the 70?"

"Only 2634. I drove through Arkansas. That saves you about an hour."

"I tried to reach you but your secretary said you weren't available. Now I know why, you must have been driving for the last three days! You know you're mad!"

Charlie nodded and smiled. "Yes, but you said mad is good!"

Spencer closed his eyes and drew the other man closer. "It is. I'm happy you came."