Title: Joining Forces

Fandom Crossover: NCIS/CSI Rating: M for later content

Pairings: Nick/Tony, Abby/Greg, Grissom/Sarah, Ziva/McGee

Summary: The Vegas CSI team catches a case involving a dead Marine and a chilling note. Nick is surprised to see an old friend when NCIS shows up on scene. When the killer targets one of their own…how will the teams respond?

A/N: Crappy summary I know but hopefully the story is good. I was daydreaming after watching NCIS and CSI in the same day…and this is what demanded to be written.

Chapter 1

"Aw man, why does it have to rain today?"

"Quit whining Nicky…it's not that bad."

"Yes it is Warrick…we're gonna catch an outdoor scene and have to go out in that…I just know it. Look at that…"

They both looked out the window at the nearly black sky that was dumping buckets of rain. Warrick grinned wide at the whine Nick gave as Grissom came through the door. Grissom raised an eyebrow as everyone laughed at Nick.

"Sarah, Catherine…robbery on the strip. Greg…court testimony at 3. Warrick, Nick…Homicide in the dessert."

Nick groaned and gave Warrick and 'I told you so' glare. Warrick just gave a hearty laugh and headed for the parking lot…nearly dragging Nick along the way. Greg was also dragging his feet…mainly because he hated to testify in court…most of the time he had to put his test results in laymen's terms which really sucked in his opinion.

Once they got to the scene Nick immediately noticed how tense the officers seemed to be. He pointed this out to Warrick as they headed to the tented area. Once they got closer they saw why the officers were tense. Their victim was a Marine…still in uniform.

"Shit…Multiple GSW Nick…this was definitely not an accident."

"Yeah…I'll go call Grissom. You start photographing the scene but don't touch anything yet."

"Got it."

Nick walked a little ways from the scene for a tad bit of privacy from the officers.

"Hey Grissom…yeah it's Nick…yes we made it to the scene just fine…we got a Marine in uniform…multiple GSW…yeah…Warrick is taking photos…no we haven't touched anything yet…the officer's put a tent over the scene, but I doubt we'll find much thanks to this storm…Alright…We'll see what we can find…Later."

Nick sighed. Hopefully NCIS would be cooperative and not combative. He went back over to the scene to tell Warrick.

"Hey Warrick…Grissom's calling NCIS. He wants us to look around and see if we can find anything in the meantime."

"Got it…hey Nick…grab an evidence bag and some tweezers…there's a note near the body."

Nick got the necessary items and returned. He used the tweezers to lift the note and slide it into the evidence bag which he quickly sealed and initialed.

"I'm only getting started…I don't like the sound of that Nick."

"Yeah…me neither man…let's keep looking."

2 Hours Later

Nick and Warrick looked up as a sleek black Charger came sliding into area.

"I think they're here."

"Really Nick? Couldn't tell."

Nick shook his head…at least the rain had stopped about an hour earlier…which is, ironically, when Grissom and Brass arrived on scene.

Nick and Warrick watched in amusement as several people jumped out of the car and nearly kissed the ground. The last one out of the vehicle was an older man…Nick was thinking maybe a Marine, definitely military training…he was sporting an amused smirk at his team. Brass and Grissom walked over and introduced themselves and talked a bit before motioning for Warrick and Nick to come over.

"These two are Warrick and Nick…they're the lead CSIs on this case.

"Alright. I'm Special Agent Gibbs. My team here is Tony, Ziva, McGee, and Abby. Tell us what you've got so far."

Warrick nodded at Nick and let him take the lead on this one.

"Well, we've got a Marine in uniform with multiple gun shot wounds. 2 in the chest, 1 in the groin, and 1 in the head. Out ME took the body about an hour and a half ago…he's currently hooked up with your ME via satellite. Warrick took photographs, and we did manage to find some evidence that wasn't washed away in the storm. Also…the killer left us a note."

Nick handed the bag with the note to Gibbs and watched the man's face darken in anger.

"I don't know is this guy is targeting just marines, all military, or what…but we're clearly dealing with the first victim of a serial killer."

"Good job Nick…My team will take lead, but I'd like the two of you to continue working with us on this if you'd like."

"Absolutely…right Warrick?"

"Yeah…something about this just rubs me the wrong way."

Nick looked at the rest of Gibbs' team and then blinked. One of them was staring at him…and he looked really familiar. Suddenly it dawned on him and he grabbed the guy in a hug.

"Tony! Man it's been awhile huh? How've you been man?"

"I've been good…single again though. When did you become a CSI?"

"A while ago…NCIS huh?"

"It's good work Nick…real good."

Gibbs was watching the interaction with a raised eyebrow, much like Grissom and Brass, while everyone else had their mouths hanging open.

"You two know each other."

"Yeah Ziva…we grew up together…been friends a long time."

"Yep…haven't talked in a few years though…we'll have to play catch-up later…for now, we have evidence to process."

Everyone went to their respective vehicles to head back to the lab…never realizing that they were being watched by a sinister presence.