Disclaimer: Abby, Dr. Mallard, Ziva, Jimmy, and Gibbs are part of NCIS, and Charlie and his brother are part of Numb3rs. Both belong to CBS and its affiliates. The victims' names and descriptions are all figments of the author's imagination. Any reference to any real person or persons is merely coincidental and accidental.

A.N. I am SO sorry everyone! I really didn't mean to keep you all waiting for this chapter! But with bad grades, stress, life, and writer's block, it took much longer that I had been planning. I hope I haven't discouraged too many people from continuing to read this, and I will try (but not promise-sorry!) to update a little sooner and more regularly than this time.

Also, special thanks to my math teacher from this past year for helping me figure out all of the calculations that are going to be used throughout the story, and for my friend Miomo for staying on my back to update this lately.

Again, thanks for your patience everyone, and enjoy the chapter!

… … … … … … … … … …

She couldn't believe it. With all the trouble Chip brought to the team, Gibbs was hiring another assistant? The team didn't know anything about this Doctor Eppes guy. All they knew was that this guy was a mathematical genius, and he had a brother in the FBI, which he sometimes consulted for.

Sitting back in her chair, drinking her Big Gulp, Abby Sciuto tried to imagine what he must look like, given the name and background information. He taught math at Cal Tech-or was it Cal Sci?- so she figured he was an uptight guy, wearing a business suit everyday. He grew up with his brother, who ended up being the leader of the FBI office out of LA. So he probably did have a sense of humor that came out occasionally, if he was anything like Gibbs. He probably would talk like he was superior to everybody, making everyone call him "Doctor Eppes." Abby shuddered at the thought. Having an assistant is bad enough. But an uptight guy as an assistant? Could it get any worse?

The elevator made its "ding" sound, and Abby turned around to get her first glance at the infamous Doctor Charles Eppes.

She was blown away by what she saw.

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Another elevator ride later, Charlie entered the lab with Ziva next to him, still carrying his suitcase for him. Looking around at he lab, he was impressed with all the equipment he saw, and of the arrangement of the room.

Sitting in the midst of the room was who he presumed was Abby. But she looked nothing like what he was expecting. He expected someone in a white lab coat, a dress shirt sticking out from underneath the coat near the neck. Instead, this woman was wearing a simple white tank top and black pants, but it was more her head that threw Charlie off balance. Her black hair was up in pigtails, she was wearing dark red lipstick, and her face was incredibly pale. What especially startled Charlie was the fact hat she had a tattoo of a spider'sweb on her neck.

"Abby, this is Doctor Eppes, but he goes by Charlie."

And before Charlie knew it, Abby had stood up, ran over to him, and gave him a bone-crushing hug, exclaiming, "I'm so glad you are nothing like what I imagined you to be!"

To say that he was shocked was an understatement.

… … … … … … … … … …

Abby pulled away from the hug, her grin spreading from ear to ear. Well, if this Is the assistant, it can't be too bad, she thought. Her smile faded only slightly when she saw that his eyes were as wide as saucers, and his jaw had dropped.

"I'm sorry, did I scare you, Doc?"

Charlie regained his composure, and his facial features resumed to normal. "More like startled me, Abby. And, as Ziva said, you can just call me Charlie."

"I know what she said. It's just much cooler to call you Doc," she replied cheerfully.

The two of them continued to look at each other in silence before Ziva broke it. "Abby, where would you like me to put Charlie's thinkgs?"

"The desk in the corner is fine. I cleaned it off for him earlier today," Abby said without looking at her. Instead, she continued looking at Charlie. "So, Doc," she grabbed him by the arm and led him over to the large screen, "I'm guessing that you want to be briefed about the case, huh?"

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Abby finally turned away from Charlie, although her hand was still on his arm. She brought up the images on the screen with the numerical patterns from the crime scenes.

"We have had 2 victims that were part of the marines, but there was another guirl that was found, a civilian," Abby stated. "We don't know yet if the killer is after women in the marines, or it's jut a coincidence.

"Nothing is a coincidence," Charlie interrupted.

"Don't say you're as bad as Gibbes on that opinion," Abby responded without missing a beat.

Charlie could hear Abby coninue talking, but his brain was no longer processing her voice. Am I really that similar to Agent Gibbs? He wondered. Is he as nit-picky about people saying there a coincidences in the world as I am?

"Doc? Are you still listening?"

"Yeah, yeah, I'm listening, Abby. Listen, I would like to see the bodies, and then I'll look at the numbers, okay?"

Abby looked a little taken aback. "Sure. If you think that will work, go ahead."

"I'm going to need a guide to the morgue, though." Charlie looked around, and saw that Ziva had already left the lab. "And as you're the only one here who knows their way around the building…" Charlie raised his eyebrows expectantly at Abby.

Abby hesistated before replying, but when she did, she was as cheerful as ever. "Well, Doc, I'd be glad to show you down to the morgue."

… … … … … … … … … …

"Now, Jimmy, be careful with that heart. We don't want to break it, as I'm guessing some of her old boyfriends must have," Dr. Mallard instructed his assistant.

Jimmy grinned as he loosed his grasp on the heart he was carrying from the body in autopsy. "Your wit never ceases to amaze me, Dr. Mallard."

Ducky heard the door open behind him, but he didn't turn around to see who it was. Who else could it be besides Jethro, anyway? "Jethro, I was waiting for you to come down. I've almost finished the autopsy on our Jane Doe here.":

"Actually, Ducky," Abby's voice responded, "We don't care much for Jane here. I brought Doctor Eppes, the new consultant, down. He wants to take a look at the bodies from the other case.

Ducky would have whipped around, had he not had his hands stuck inside a dead body on the table. "Doctor Eppes? As in, Doctor Charles Eppes?" He finally pulled his hands out of the body in front of him and slowly turned around.

"Yep, that's me, Duck." A slightly childish grin grew on the goung man's face. "How have you been?"

"Never better, Charles."

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Doctor Eppes? As in, Doctor Charles Eppes?"

Charlie was slightly surprised to hear Doctor Mallard ask if it was truly him. Perhaps they didn't tell him. But why? "Yep, that's me, Duck," Charlie greeted the old aquaintance. A grin spread across his face, and as much as he tried to stay at least a little serious, he was sure it looked pretty goofy. "How have you been?"

"Never better, Charles." Ducky pulled his bloody gloves off and threw them in the waste bin before offering a hand to Charlie. "And you?

"Same here." The grin refused to leave his face as he shook the hand held towards him. "It's been much too long since we last met, though."

Abby interrupted the reunion to ask, "Are you two trying to tell me that you know each other?

"It was several years ago, Abigail," Ducky began. Charlie was pleased to notice that he wasn't the only one Ducky called by his full first name.

"Around ten years ago, actually. We were at a convention of sorts, for different sciences," Charlie continued.

"Was it really? Has it truly been that many years?" Ducky asked, clearly astonished.

Charlie nodded. It had been. He could remember going like it was yesterday, though. A simple weekend conference in Las Vegas for scientists of different fields. Larry had somehow convinced Charlie along, thinking it would be a good experience for him, as well as a chance to get out of his garage for a week. His whole family seemed to be for the idea as well.

"Come on, Charles. Your talent would be helpful for some of the scientists there. The whole idea of the conference is to share different ideas and connect all of the scientists together. Your knowledge of mathematics is sure to bring insight into some of their projects, and the chances are high that you'll learn something yourself."

Indeed, he had learned new facts there. No one gave him so much interesting information as Doctor Donald Mallard, though. And he seemed to be interested in Charlie's math.

"Someday, Charles, I'm sure you will become known for your work. Not just for your math itself, but also for how it helps thosse that wish to believe that it has no use to them. And when you do, you'll have to come back and tell me all about it."

"So you've convinced people that your math can be used?" Dr. Mallard asked him. "I daresay it will help with this case. Let me show you the bodies, then."

"While you do that, Ducky, I'm going to head back upstairs." Charlie turned around in time to see Abby make a quick exit from the room.

"We currently have three victims, all female. Two of them were Marines, and one of them is a civilian. We don't know if the killer is going after service women or not, although we're guessing he doesn't have a preference one way or another." Ducky rolled out each body, one by one, as he was talking. "All of our victims were strangled with sturdy rope, although it wrapped all the way around the neck."

Charlie walked around, inspecting all the bodies. "They were strangled, you say?

"Yes. We collected rope fibers, and found that the rope used comes from any standard hardware supply store. We couldn't trace to which one it was."

Charlie pointed to the neck of one of the girls. "Then why is her throat slit?"

"That was performed post-mortem, Charles, possibly to cover up the bruising from the strangulation. The girls experienced no knife cutting into them when they were alive."

Charlie nodded as Ducky continued. "Each of the girls came with a note, including the non-marine. It makes me wonder whether our killer was specifically going after marines or not."

"What was the order of the girls' deaths?"

"The first one, Carrie Maskovy, is the blonde girl over there. She was one of our marines. The second one was also a marine, Lily Small, the brunette on this table. Our non-marine was the last of the three to be killed, Sasha Brewer," Ducky replied. "As I said, each girl came with a note, filled with numbers that none of us could make heads or tails out of. That's where you come in, I assume. Abby has those notes upstairs. I don't think there is much more I can do for you down here, Charles."

"Thanks, Duck. This has been very informative. And it's good to see you again."

"Same with you."

Charlie continued to process all of the other information as he headed back to the elevator, added to the attempt to remember what floor Abby was on.

Why can I remember thousands of complex formulas and equations, but not what floor to get off at while on the elevator?

… … … … … … … … … …

The doors to the lab opened, and once again, Doc came strolling into the room.

"Alright, Abby, I'm ready to see those notes that were found with the victims," he told her, not even fully across the room.

"I figured you would. I've gotten them out for you already."

Doc took the three of them and put them next to each other on the table, making sure both of them could read it. All of them were nearly identical.

6.28

2/1

7

6

The third to last line held the only differences. The first letter simply had a 5, the second, a 4, and the third letter, a 3.

The letters continued, once again identical in the numbers.

36, 10

115, 10

"It's not as cold as we thought," she heard him mumble before running back out of the room.

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Charlie couldn't believe his eyes. The papers weren't making entire sense, but he knew that something was up.

Running for the elevator again, Charlie tried to figure out what to tell Agent Gibbs. As a familiar ding sounded, he almost ran into the exact person he was looking for.

"Agent Gibbs, the numbers that Abby showed me. They are the same as the case we just worked on in Los Angeles."

"What do you mean?"

"The notes that we got on our last case there were almost exactly the same as the ones that are here. I never saw the bodies there, but I'm willing to bet they have the same injuries as the three women that died in this area."

"Are you saying that this killer has been moving from area to area to commit these acts?"

"I think so, Sir."

"And you had a cold case there?"

"That's right. Fortunately and unfortunately, we didn't have enough information to find the guy. We now have more data to examine."

Agent Gibbs paused for a single second before giving his next order. "Call your brother. Tell him to get onto the next flight out, and bring the information from the last case with him. The more people that are working together to nail this guy, the better."