Author's note: I was watching 'Twisted Sister' and an alternative reason for McGee's weight loss occurred to me. This will be the first in a loosely connected series. F.

Disclaimer: I don't own any characters etc

It was Abby that noticed it first. Curled up beside him, she traced the contours of his shoulders and chest and commented

"I think you've lost weight"

Amused, he laughed a little

"Wishful thinking, Abs"

She sat up

"I'm serious, Tim, I swear you've lost weight"

Now that he thought about it, it was possible. His clothes weren't exactly hanging off him, but they were a bit looser. But it didn't make sense. What would be causing him to lose weight?

"You could be right" he allowed "But why?"

She smirked at him.

"All that extra exercise?"

He thought back over the past few months. They'd been dating for about 8 weeks now; in secret, partially to avoid the problems caused by Gibbs knowing about them breaking Rule 12. And in those 8 weeks, she'd spent almost every night in his bed. It was a side effect he hadn't expected...

...

It had all started a little over 2 months ago. She'd been bugging him all day to go clubbing with her. Normally he avoided Abby's clubbing nights; usually she went with DiNozzo. But this time round, he already had plans that he refused to break, and there was a new club opening that she was desperate to go to. He always found it close to impossible to resist giving in to Abby's requests, and this time was no different. She'd looked at him with a pleading look in her big green eyes and he'd caved.

The club had been everything he'd imagined. Loud, crowded, expensive and filled with people at least 10 years younger than him. Abby had loved it, insisting that he dance with her. Normally not a big drinker, it seemed natural in the surroundings to buy a round to cool off after trying to keep up with Abby. That first round had turned into another, and another, until they'd wound up doing shots of tequila, something he never did. Having drunk just enough to make self control seem overrated, their usual light hearted flirting had quickly become more serious, more in earnest. They'd ended up going back to Tim's apartment together.

Once the shock of waking up with Abby in his bed, along with a slight hangover, had worn off, they'd quickly decided that going clubbing had been the best thing to happen to them. They'd also decided to keep their new found relationship a secret. It meant some quick thinking from time to time, and the occasional red herring.

...

A few weeks later...

"Tony's going to notice" Tim pointed out. Actually, he was pretty sure the whole team would notice, being the highly trained investigators that they were, but Tony would be the one to comment on it. His weight loss had continued, and it was becoming obvious that his clothes didn't fit any more

"Especially if you lose any more, Tim" Abby laughed. She quite liked his slimmer figure. "We're going to have to come up with something"

"I think new clothes are in order first" he said gloomily. If he lost any more weight, he was going to look like he was wearing hand me downs.

She was perched on the edge of his desk, waiting for him to finish up the case report he was working on so they could go. Everyone else had gone a far while ago, leaving them alone in the bullpen. He hit 'save' and turned his chair away from the computer.

"Ready to go?" he asked. She slid off the desk, and then stopped.

"Got an idea" she spun back to his computer and opened his electronic datebook.

"There"

He looked over her shoulder at the screen

"Good idea, Abs. One problem though... no one is going to believe I have personal training 4 times a week" he pointed out

She gave him a mischievous grin

"I know, but it gives you an excuse to have plans those nights. Two birds with one stone"