AN: It was a comment from Ryuze that finally convinced me to cross post this here. There really aren't enough of these fics around.

This was written for a Livejournal prompt. Only the first hostage in TGG happened. Sherlock called Jim, figured out who he was, and now Jim comes to harass the consulting detective at 221B when they're both bored.

This is all written, but I'll probably post chapters about two days apart so I have a chance to consolidate and edit.

"Oh, hello. Jim from IT, right?"

"James Moriarty actually. Hi!"

John froze. "Sherlock! Why is there a criminal mastermind in our living room?"

"Because we're bored," the detective called back

John took several moments to think things over. Several long moments. "Is anyone being hunted by a mad cabbie or a Chinese crime syndicate at the moment?"

"Not that I'm aware of," Jim offered.

"Right then. Don't blow up the flat."

Pertinent questions settled, John turned his attention back to the shopping. "Is there anything that would bother me in the fridge?" he yelled in the general direction of Sherlock's room.

Jim didn't quite know how he felt about that. He'd been expecting fear, shouting, at least an attempt to inform someone else. Not mild irritation followed by calm acceptance.

Sherlock, strolling out of his bedroom, took one look at Moriarty's face and quirked his lips. "Yes. He's always like that." Throwing himself down onto the couch, he turned his attention to John. "Define bother."

"Things that would send a sane person running and screaming."

"Yes, there are quite a few items in the fridge that would 'bother you'."

"Right then. Is there anything in this fridge that will kill me upon its opening or poison food placed nearby?"

"If you stay away from the top shelf, you should be fine," Sherlock remarked. As John started putting the shopping away, he turned his attention to more interesting matters. "You repeated yourself. You're creative enough to come up with something better than botulism, at least the second time."

"Second time. Wait, second time? Moriarty's the bomber?"

"Obviously," Sherlock replied.

John poked his head back into the living room, wearing the expression Sherlock had learned meant he was trying to figure something out. "I'm not complaining, mind, but there were five pips on that message. I thought that meant that I'd have to convince Sherlock to give a damn about four more people."

"Too predictable," Moriarty offered.

"No. That's not it. Genius needs an audience. You don't mind being just a whisper, but you're too good at what you do. You wanted acknowledgement. In the end, you decided that playing with Sherlock, entertaining each other, was better that eliminating interference. You decided he was more useful than irritating." John looked at Moriarty's expression, nodded to himself in satisfaction, and then went back to unpacking the shopping.

Jim just stared after him, shocked. Sherlock took in the familiar expression and then smirked. Jim shot him a sharp look, eyebrow raised in inquiry.

"Wolf in sheep's clothing," was all he offered on the subject.

Silence reigned for awhile before Sherlock interrupted again. "Ian Munkford and the Lost Vermeer make four. Was the missile plans five?"

"I had nothing to do with those. I could get them anywhere, if I wanted to. No, five was where I killed you." Jim shrugged, and then smiled. "This is more fun," he said, staring in the direction of the kitchen.

Moriarty turning up in the flat was becoming such a regular occurrence that John had started brewing enough tea for three.

John passed Moriarty a cup, placed one on the coffee table Sherlock had a bad habit of walking over, and sat at the table by the window across from the consulting criminal.

"Sherlock's not in at the moment. I think Lestrade finally managed to drag him in for a statement," John informs him, shaking open the day's paper.

"Why doesn't this bother you?" Jim asked, his head tilted and eyes intense as he considered the most puzzling person he had encountered in decades.

"If you're here, he's entertained. You're also not out killing people. If I can keep an eye on both of you I know you're not off…I don't know…blowing up a public building or taking over the world or giving LSD to control groups because you think its funny. It keeps you both entertained and keeps me sane. Well, mostly sane. If I was ever sane to begin with. Anyway, I think it's a very good system."

Filing away the LSD comment for a rainy day, Jim looked at John Watson for the first time. Really looked, not just the cursory "figure out your life story" glance. Short, sandy hair smattered with grays. Deep, dark blue eyes that had seen too much yet wanted to see more. Eyes surrounded by laugh lines and underlined by dark circles. Steady hands that could take life just as easily as save it. A contradiction.

Jim had to admit, he really, reallyliked what he was seeing. He wanted to see more. But that stupid woolly jumper was in the way. Jim didn't care for the sheep's clothing – he wanted to see the wolf underneath.

Jim began eyeing his tea speculatively. It wouldn't be too challenging to ensure John thought it was an accident. The difficulty was to spill just the right amount. Too much would soak through to the undershirt, and then John would go upstairs and change instead of just removing the wool monstrosity. Too little and John would just dab at it and ignore it. Two tablespoons should do the trick.

Jim had his calculations right; a stain about the size of a handprint bloomed across John's jumper. The door opened downstairs, and Jim could tell from the stride that it was Sherlock, but he had better things to concentrate on at the moment.

John waved off the apologies that Jim had only just realized he should start forming, excusing himself to go change.

"Why? Why not just take of the jumper?"

"Since someone," a pointed look here, "blew up the block of flats across the way, and consequently blew out our windows, it has been far too cold to sit about without at least three layers." The door to the flat opened and John lips twitched into a small smile that seemed almost instinctual.

It makes Jim want to overthrow a country. A continent, really. Australia, perhaps? If he gave it to John, would he receive the same smile? Or was an evil mastermind offering Australia to someone whose favor he wants to curry too cliché?

"Oh good. Sherlock, you and Jim keep each other entertained while I go change."

"Why do you need to change?" Sherlock asked, eyeing the stain on John's jumper. "The angle is all wrong for you to have spilled it on yourself." His eyes rested on Jim's teacup, then Jim before growing cold and hard. "Ah. I see."

As soon as John was out of sight, Jim was out of his chair and Sherlock was looming above him, trying to look impressive and dangerous in his charcoal coat. Jim wasn't intimidated.

"He is mine," Sherlock hissed. "He is good, and broken in all the right ways and you are not to touch him again."

"He's not yours. Not yet," Jim responded, voice filled with an ice-cold fire that sends other criminal masterminds cowering.

"Well, he certainly won't belong to you."

Jim had killed men, women, and children without remorse to get what he wanted. One little consulting detective, brilliant and entertaining as he may be, wasn't going to stop him. Playing with Sherlock had been fun, but he had always intended to crush him in the end.

Oh. Oh. Was that a wonderful idea if he ever thought of one.

"Sherlock, would you like to play another game?"

The terms of engagement were straightforward. They may each kiss John once and may use any excuse to touch him, but all other advances must be made by Dr. Watson. The first one who John confesses he loves is the winner. To the victor will go the spoils. The loser can sod off.

John returned from upstairs, now clad in a generic green button up that didn't fit right and a patched coat. It wasn't quite what Jim had hoped for, but it was a marked improvement over the jumper. Jim made a mental note to have the windows at 221B fixed and to rig the heating. Also – find plausible excuse for destruction of all John's clothes, particularly jumpers, and convince the man to allow the purchase of designer replacements.

"One point on which we are entirely in agreement," Sherlock commented, having no trouble following Jim's thought process. "The first half should be accomplished with relative ease. It might take our combined efforts to achieve the second, however."

"Fine," Jim said sharply, thinking. He needed to come up with a complicated crime that he could use to completely humiliate the detective and impress John. No murders then. Pity, Jim had a flair for those. Elaborate embezzlement scheme? Counterfeiting, maybe?

John glanced back and forth between the two consultants. "Have you two had a row?"

Sherlock shot him an icy glare. "I do not," he said seriously, "have 'rows'." He sniffed, insulted by the very idea.

"Fine, started a feud or whatever you want to call it."

"We've decided to play another game," Jim offered. He knew from his surveillance that John hated it when Sherlock kept things from him, and he felt John would appreciate the effort to keep him informed.

A long pause while John thought. "Is it going to negatively affect anyone outside this flat?"

"No," Sherlock responded.

"Well, you two have fun then."

Sherlock made his first move that afternoon while John was at the surgery. Jim stuck around, knowing it would backfire spectacularly and wanting a front row seat.

John, looking tired and haggard, trod slowly up the stairs to his room. There was a long pause, and then the footsteps returned with force to spare. John's usually expressive, emotive face was perfectly blank – the way nature stands absolutely still before a natural disaster.

Jim had to fight incredibly hard not to grin like the madman he was. He didn't think he'd ever been this excited about anything since he first got started in the criminal world. This was so much better.

"Sherlock," John said, voice soft and calm. "Would you kindly explain why my room looks as if it has been set ON FIRE?" His volume increased on every word.

"Because it has," the consulting detective replied as he tuned his violin.

"Why? And so help me, if you say it was and experiment I am going to wring your scrawny little neck, Mycroft be damned." Sherlock said nothing. "Do you have any idea how much this is going to cost to fix? Everything I owned was in there, Sherlock. Everything. Where the hell am I supposed to sleep?" A long, deep sigh.

"You could sleep in my room," Sherlock offered, expression, carefully blank. John's glare quickly shut down that idea.

"I need some air. And I'm kipping at Sarah's tonight. Don't wait up."

John slammed the door behind him.