Disclaimer - I don't own CSI; NY or NCIS.

A/N - This is a crossover between the two series. With NCIS it begins a year after Tony joins Gibbs' team, no Kate or McGee yet. With CSI it begins a year before Season One.

Warnings - Slash (lots of), multiple pairings and MPREG.

One Night Stand

Prologue.

Upon waking the hangover hit him like a truck but the memories of the night before didn't, they took a few moments of lying there in agony to remember just what he got up to at that party that Tony had literally dragged him to. When they were finally clear in his mind they hit him more like a train, as had the lithe body lying asleep next to him. He, Leroy Jethro Gibbs, had gotten drunk and had sex with a stranger, a very handsome, male stranger.

"Oh shit," he hissed, almost smacking himself on the head before he realised how much that would hurt with a hangover. Instinct took over quickly and he slipped out of the unfamiliar bed and searched from his clothes, pulling them on quickly, the quicker got out of here the quicker he could hide what had happened. What he didn't know was that the man still lying on the bed was no longer asleep and was now watching the older man calmly, sadness in his light blue eyes as his partner from the night before hurried to get away. "Where the fuck are my shoes?"

"I'd try the other room," the other man finally spoke. Gibbs' head snapped up, staring worriedly at the younger man. "I remember loosing most of my clothes and shoes in there so yours might be there too."

"Thanks," Gibbs said awkwardly, turning to leave the room.

"Don't I even get to know your name?"

"I thinks it's better if we didn't, I mean I don't normally…" Gibbs was at loss as to what to say and that didn't happen often to the NCIS Special Agent.

"That's alright," the man sighed and turned his head away, "It was nice meeting you." The man stayed turned away as Gibbs left the room, found his shoes amidst the other clothes and then left the room which turned out to be on the second floor of a cheap hotel. If Tony had seen him leave the club with the other man he was never going to live it down.

Flack stayed still in the bed, facing away from the door and listening to the sounds of his sexual partner leaving. He himself hadn't been too drunk last night, could remember almost everything that had happened. The pair had chatted at the bar, Flack had suggested a walk for some fresh air. They'd walked, chatted and ended up kissing each other senseless. It had been the other man who had hailed a taxi, ordering the driver to go to a cheap hotel nearby, it was the other man who had paid for the rooms. Flack however had been the one to initiate the rest of the nightly activities even though he had been bottom all three times.

The night before had been the first time in a long time that Flack had hooked up with someone from a club and the first time in maybe years that it was a guy, mostly it was girls who wanted to go to bed with him and only then after a few dates. Last night had also been the one he'd enjoyed most in the last few years. It really was a shame that the other man obviously didn't feel the same way, the other man definitely wanted to forget it even happened if his hasty escape was anything to go by.

A/N There you go and as a treat here's chappie one…