A/N: Thank you to Ariane DeVere for posting Sherlock episode transcripts on LiveJournal! Any recognizable dialogue here is from "A Study in Pink." I don't own these characters, Moffat/Gatiss and Conan Doyle do.

Mike Stamford was worried. He was lecturing on prostate cancer in thirty – no, bloody hell, twenty – minutes and he hadn't the slightest clue where to find the histopathology slides for his lecture. His last resort was the lab on the 5th floor; he was trying to avoid it because he knew Sherlock Holmes would be in there experimenting and wouldn't want to be disturbed. Much as he feared Sherlock's temper, he decided that he'd rather face the wrath of one consulting detective than the wrath a lecture hall full of students. (Or worse, the dean, if word of the mishap got round to him, which it certainly would.)

"Morning, Sherlock," Mike said as he rushed in.

"The histopathology slides are over there," the detective said. He pointed to a shelf in the far corner of the room without looking up from his microscope.

Mike was about to ask him how he knew that but thought better of it. "Thanks. Moved into the new flat yet?"

"Yes. Lovely little place but the rent's a bit expensive."

"Brother won't help you?"

The detective snorted. "I wouldn't take his help even if he did offer it."

"Why not just get a flatmate?"

Sherlock arched an eyebrow. "Who'd want me for a flatmate?"

Mike thought for a moment. He'd always respected Sherlock's honesty and he knew that honesty was one of the reasons Sherlock liked – er, no, tolerated – him. "I've no clue, Sherlock, but if I find someone, I'll be sure to tell you."

The detective mumbled his thanks and dove back into the microscope. Mike retrieved the slides he needed and walked off to his 11 AM lecture.

(Who could be the flatmate of Sherlock Holmes?) He needed someone with a thick skin, that was certain. Someone who wouldn't burst into tears the first time Sherlock shouted at him to shut up. Sherlock would also need someone who was relatively bright. Of course, no one is as bright as Sherlock, but he'd need someone with at least a prayer of keeping up with his mind. The flatmate would need a high tolerance for dirt, grime, and body parts from the morgue. (Going by the state in which he leaves the lab, his flat must be just this side of a landfill in terms of cleanliness.) And the flatmate would need an infinite supply of patience. Mike knew Sherlock kept odd hours and the man could be somewhat abrasive even with people he'd just met; God only knew how he'd act at home. Anyone who wanted to come home to a cup of tea, telly, and an early bedtime would not last a day with Sherlock Holmes.

Above all, any flatmate of Sherlock's would need a bloody good sense of humour. Mike usually found Sherlock's brusqueness amusing rather than offensive, and he supposed that was another reason he got on with Sherlock. (At least, I get on with him as much as anyone can get on with Sherlock Holmes.)

Mike put the thoughts of the consulting detective and his housing dilemma out of his mind and entered the lecture hall. (Bright young things, eager to learn… it's both lovely and disgusting.)

After the lecture, he decided to take advantage of the lovely weather and have lunch outside. As he sat on the park bench, he didn't take much notice of the passersby. When the young bloke (forty is still young, right?) with the cane limped by, Mike scarcely noticed him at first. But there was something familiar about him that made Mike look again… oh, of course!

"John! John Watson?"

The man turned around, clearly struggling to recognize him. (Right. I've gained at least 3 stone since Bart's.) The overweight professor added, "Stamford. Mike Stamford. We were at Bart's together."

A bit embarrassed, John replied, "Yes, sorry, yes, Mike. Hello, hi."

Mike gave a self-deprecating grin and said, "Yeah, I know. I got fat!"

"No."

"I heard you were abroad somewhere getting shot at. What happened?"

"I got shot," John said.

It was then that Mike noticed how much older his friend looked, and that it wasn't merely the passage of time that had aged him.

Mike urged the limping John to sit down while he fetched them coffee from a nearby stall. He insisted on paying; it was the least he could do for a war hero. He sat next to John on the bench, handed him a coffee, and pretended not to notice the tremor in John's left hand. (He must have had some nerve damage, and it bloody would have to be in his dominant hand. Not only is he out of the Army, he probably can't practice medicine. What a terrible blow.)

The two men updated each other on what they'd done since graduating from Bart's so many years before. The veteran revealed that he was probably not going to stay in London much longer. The city was simply too expensive for a man on an Army pension. Mike asked if he'd tried looking for a flatmate.

"Who'd want me for a flatmate?"

He sized up John. (Whatever Sherlock's flat looks like, it's got to be better than where John camped in Afghanistan. He's an Army doctor, so he can handle Sherlock's experiments on body parts. Always known him to have a good sense of humour, played a few pranks his day and when he was on the receiving end, he took it in stride. And anyone who could get me through biochemistry has the patience of a saint. John Watson thrives on challenges, and living with Sherlock Holmes is likely the greatest challenge he'll find in civilian life.)

Smiling slightly, Mike said, "You're the second person to say that to me today."

"Who was the first?"

Mike invited his friend up to the lab where Sherlock was working. He watched John's expression as Sherlock deduced him and stifled a chuckle as Sherlock rattled off his deductions about John's sibling. (I'd love to see the look on Sherlock's face when he finds out that Harry is John's sister.)

After Sherlock swooped out, John gave Mike a quizzical look.

"Yeah, he's always like that."

"Right, well, I'd better be getting along then," John said.

"So are you going to meet him?"

"I suppose I've nothing better to do," John grumbled.

Something about the expression on John's face sent a pang of concern through Mike. "John, before you go, could I get your phone number? I'd like to keep in touch."

Keep in touch they did, and as Mike predicted, John moved in with Sherlock Holmes. After he read John's blog entry on the serial suicides, Mike grinned from ear to ear. One didn't need to be the world's only consulting detective to figure out who shot the cabbie, or to deduce why Sherlock was suddenly trying to be a little less offensive. Mike had only intended to help the two men save a little money on rent; instead, he'd combined two usually unreactive compounds and caused a reaction with an extraordinary product.

All they had needed was a catalyst.