A/N: This is my submission for the CCOAC Crossover Challenge. My character was Ziva David from NCIS and my CM character was Aaron Hotchner. Just to let everyone know, this is NOT my big NCIS/CM crossover that I'm planning. I'm not sure when that's going to be up.

The only kind of romantic pairing in this is Tiva, and even that isn't huge.

I hope you enjoy the story! Let me know what you thought at the end!

Ziva David blearily tried to focus on the computer screen in front of her without having her eyes fall shut. It was approaching midnight, and she was still at NCIS headquarters. What was worse was the fact that she hadn't gotten a suitable night's sleep in many days.

The case they were working on was bad. No, it was more than bad. It was awful. Six women were dead over a span of six weeks. They were abducted Friday night, and then found dead Monday morning.

NCIS hadn't even been a part of this case at the beginning. It was originally the FBI's case, but when the latest victim turned out to be a Navy Lieutenant, Gibbs demanded to help. And so, Ziva's team was working with the Behavioral Analysis Unit.

In only a matter of hours after the most recent victim, Clara Turner, was found, the BAU had taken over NCIS' bullpen with all the evidence from the past five murders. They worked closely with Ziva's team, and in the process, made new friends.

Sadly, now was not the time for that. It was Thursday night now, and Friday was fast approaching. They needed something they could work with, but everything so far had been a dead end.

Rubbing her eyes for the millionth time, Ziva scrolled through Clara Turner's bank records yet again, trying to see if they missed anything. They were desperate for any lead.

"Found anything, Ziva?" Leroy Jethro Gibbs asked, striding into the dark bullpen. Close behind him was the BAU's Unit Chief, Aaron Hotchner, or Hotch as he insisted to be called.

"No," she grumbled. "There is nothing in these records to suggest she was anything extraordinary."

"Maybe we're looking at this the wrong way," Hotch mused, staring intently at a bulletin board covered in pictures, note cards, and maps.

"How have we been looking at it?" Ziva asked, standing up to join the men. If she didn't get moving, she would fall asleep right there.

"We've profiled this UnSub to be targeting these victims specifically," Hotch explained. "This kind of killer usually does. However, what if he isn't?"

"Are you saying these are all victims of opportunity?" Gibbs asked skeptically.

"Some of them may be. There were a few connections between the first few victims, but those disappeared. However, the victimology remains true: Attractive women, mid to late thirties, rich husbands, abducted from fancy social events."

"So the UnSub is just trying to satisfy his need to kill?" Ziva questioned.

"Most likely," Hotch answered gravely. "And judging by the torture on previous victims, he's not going to stop anytime soon."

Gibbs sighed as he checked his watch. "It's Friday. This bastard's gonna strike tonight. We need a plan." He and Hotch shared a knowing look, and Ziva began to think they already had something in mind. Gibbs turned to the Israeli woman.

"Go home, Ziva," he said softly. "Try to get a few hours of sleep."

"Maybe I should just stay here," she suggested. "That way I'll be close by."

"That's fine. Just go get some rest. We have a lot of planning to do later."

Nodding, Ziva shut down her computer before saying goodnight to the men. As she made her way to Abby's lab (the forensic scientist would have no problem with letting Ziva use her futon) a feeling of unease began to build in her stomach. Her gut told her this case was not going to go very well.

A few hours later, the two teams stood in the middle of the bullpen. Ducky and Palmer even emerged from autopsy, and Garcia and Abby were standing in the back.

"Okay," Hotch started, looking at everyone surrounding him. "As I'm sure you are all aware, the UnSub is going to strike again tonight, which means we need a plan."

"Unfortunately," Gibbs continued, "We don't have much to go on. The only thing we can do," he sighed somewhat reluctantly, "is send two agents undercover."

That got a mixture of two responses: Surprise from the BAU and acceptance from NCIS. They were more used to undercover ops than the BAU.

"Now," Hotch said, trying to bring everyone's attention back to the matter at hand. "Thanks to Garcia's computer skills, we were able to find a party scheduled for tonight that will appeal to the UnSub. It's all a matter of deciding who is going to do it. After that they will spend the rest of the day finalizing plans and their identities with Garcia and Abby."

"Ziva," Gibbs said. "We decided you would be best for this operation. You've had experience undercover, and you fit the UnSub's type." Ziva nodded, though her stomach clenched tightly at the thought of being a target.

"I'll be the man," DiNozzo said suddenly. Everyone shared knowing looks. It was no secret that the NCIS agent had feeling for Ziva. The BAU had picked it up almost immediately. Morgan and Garcia made a deal with Abby and McGee to try to get the two together once the case was done.

"I don't know if that's a good idea, DiNozzo," Gibbs replied. "You'll be recognized."

"What? How?"

"Your father," Gibbs answered simply. "It seems some of his 'business associates' will be there tonight."

"Well, then who's going?" DiNozzo asked. He needed to have a talk with whoever would be with Ziva tonight. If she got hurt…

"I think Hotch should do it," Rossi said quietly from where he stood next to Ducky.

"Why me?" Hotch asked irritably.

"I understand what he's saying. You fit the profile of the husbands the victims had," said Morgan. Everyone nodded in agreement.

Hotch sighed. They were right. All of the victims' husbands were in their forties, handsome (not that Hotch thought he was handsome, but he had heard some female agents talking), and rich. Now, Hotch wasn't rich, but that could easily be faked through some computer skills.

"Alright," he said finally. "I'll do it." He didn't miss the scrutinizing look DiNozzo gave him.

"Okay," Gibbs said, ready to get the ball rolling. "You and Ziva should go get some nice clothes for the party. DiNozzo and Morgan, I want you two organizing security. McGee, work with Garcia and Abby on IDs for Hotch and Ziva."

"Reid can help with that," Hotch said quickly. Gibbs nodded.

"Once you're done, come find Rossi, JJ, and I. We'll be getting them into the party as well as making sure other people don't get in the way." He nodded to the group of people standing around him. "Let's go."

Several hours later both teams were back in the bullpen. It was almost time for everyone to get into their positions for the night. Garcia and McGee would be in a surveillance van a few blocks away from the party. Morgan, DiNozzo, Gibbs, and Rossi would be walking the perimeter around it, and JJ would stay behind with Abby and Ducky.

Ziva looked absolutely stunning in a long black dress with thin straps. A shawl sat loosely on her shoulders. JJ, Abby, and Garcia had fun styling her hair into a low bun, leaving a few loose strands framing her face. A pearl necklace hung from her neck, silently letting people know she came from money. Hotch looked handsome in a pressed tux and white dress shirt, and he kept adjusting the thin black tie that hung around his neck. Both of them wore fake, gold wedding rings.

"Ziva," Garcia said suddenly, pushing through the small crowd. She handed the NCIS agent a diamond brooch. "Put this on. It has a camera in it that will allow McGee and I to see what's going on inside. If anyone asks, your lovely husband gave it to you for Christmas."

Morgan snickered at that, but stopped when he saw the glare from Hotch.

"Okay," Gibbs said. "Let's go through it one more time." He gestured for Ziva to start.

"My name is Isabella Montgomery," she rattled off. "I'm married to the very rich James Montgomery, have been for two years. Yes, I am from Israel, but I haven't been home in years. I moved to the States once I met James. No children because neither of us want to bring another person into the world. I have no job because my husband provides for me."

Hotch picked up where she left off. "I'm James Montgomery, head of a massive shipbuilding company overseas. The reason my work is overseas is because my father started it over there, but I prefer to live over here. I met Isabella in London five years ago, proposed after three. In addition to owning my father's company, I'm heir to his fortune. We just moved to DC from Philadelphia, which is why no one knows us."

"Okay," Gibbs nodded. "Good."

"Once you get to the party, walked around a bit," Rossi said. "Mingle with the other guests. Make sure they know who you are and that you have money. With any luck the UnSub will see you and make his move. We'll move in at that point."

"Garcia and I will be watching everything that happens while using facial recognition on the people you see," McGee said. "We can communicate with you two through your concealed earwigs."

"Got it?" Gibbs asked. When they nodded, Gibbs said, "Alright. Let's go."

Ziva began to walk to the elevator, but Hotch stepped over to DiNozzo. He knew the NCIS agent wasn't pleased with the arrangements, and he wanted to try to soothe the other man. Hotch was aware of the friendships that had sprung up in the past week, and he didn't want to ruin them.

"Agent DiNozzo," he said. DiNozzo glanced at him with a small frown.

"Yes?" he asked coolly. Hotch inclined his head to indicate the need for privacy. DiNozzo nodded and walked away from the group.

"I know you're not happy with how this is going down," said Hotch. "I just wanted to tell you that I'm going to take good care of her. She won't get hurt tonight."

"What?" DiNozzo asked. "I don't know what you're-,"

"Please, DiNozzo," said Hotch, holding up a hand to silence him. "I know you care for Ziva. You don't have to be a profiler to tell. That's why you wanted to go with her tonight. But you're not. I am. But believe me, she won't be harmed."

DiNozzo's face softened slightly. "I believe you. Just don't prove me wrong." He gave Hotch a look that suggested he would not be afraid to hurt him if she was hurt.

Hotch nodded and turned to join Ziva by the elevator. She gave him a curious look when he walked up.

"What was that about?"

He glanced at her. "Nothing." The silver doors slid open, and Hotch gestured for her to enter. Now was not the time to worry about other people's relationships.

It was time to work.