Author's Note: Thanks to my lovely, lovely beta, strangegibbon, who as always made this better than it was before.

And thanks as well to Pat-is-fannish, for services above and beyond.

Sniffer Dog

The first time Robbie MacIntyre met Sherlock Holmes—well, not met him exactly, because they weren't introduced, but was in the same room at the same time—DI Lestrade's people had found the body in the wall just where Holmes had said it would be, and the man had spun triumphantly on his heel and laughed.

"Jesus Christ," Dr Anderson had said, appalled. "What a bloody freak." And Robbie hadn't liked Anderson from that moment on because the way he talked about Holmes had reminded Robbie of the way some of the constables used to talk about Jamie when she was just doing her job and doing it damned well. Besides that, he had heard the man use "bitch" as an insult, which was not a fit way to think of woman or dog.

Robbie liked dogs. He understood dogs. Jamie had been the best cadaver bitch he'd ever been privileged to see work, the reason he'd gotten onto the Dog Unit to begin with. An absolute bloody genius of a nose, but she got sod-all respect because know-nothing dicks got weirded out around dead things.

Robbie liked Holmes, too. People who meant one thing but said another troubled him. When body language and words weren't congruent, he was always waiting for the stab in the back that was surely coming. Dogs never did that, never pretended to like you when they didn't. When Holmes didn't like you, he said so. You knew where you stood with him. Also, Holmes had the good sense to smell things as well as look at them, which just showed he was less of an an idiot than most humans.

# # #

Robbie wasn't currently on the Dog Unit (or the Dog Squad, as they called themselves, never mind the bloody public relations). He'd transferred back onto the street eight months ago, after some lowlife piece of shit hiding a meth lab had set a bear trap under snow and Casey'd lost the lower half of his leg and been retired.

As far as Robbie was concerned there wasn't a human alive who deserved a dog's love and loyalty, but you could at least try to be worthy. You could start by taking care of your partner when he was too injured to keep working, and if that meant going back onto the beat for a while, well, that was fine. Casey would have given his life if Robbie had ever needed him to. The least Robbie could do was give him a few years of his own.

# # #

If anyone had asked him, Robbie could have told them the way they were handling Holmes was all wrong. They were giving him lots of attention for behaviour they didn't like, and for a man or dog as lonely as Holmes, even negative attention was better than being ignored.

But nobody thought to ask, because a quiet man with a North Country accent clearly wasn't very bright, and anyway they'd already made up their minds about Holmes.

# # #

The first time Robbie meets John Watson he thinks finally somebody who knows how to do things properly is teaching Sherlock Holmes how to get on. Watson's free with his praise for the right things, he's good about correcting and then ignoring bad behaviour, and he seems to understand that when a man or a dog has done a hard task, he needs to self-reward.

Of all the things Robbie resents most on behalf of his cadaver dogs, it's the notion that the dogs should be sorrowful when they find a body, which is bloody hypocritical because the police themselves don't do that, can't afford to let soft emotions get mixed up in it that way. No, when a dog finds what he was set to find, be it a lost toddler in the woods or a bomb in the Underground or a corpse, he has a right to celebrate. But because civilians are squeamish about cadavers, a handler learns to take his dog off somewhere out of sight to throw his favourite toy and make a fuss over a job well done, and Watson seems to have figured that out.

# # #

Holmes starts showing up in the papers and on telly. Robbie thinks it's a bad idea; generally, the best working dogs aren't the ones suited for community work. But Watson seems thrilled that his flatmate (and no-one will ever convince Robbie they're not more than that, not with that body language) is finally being as admired as he ought to be.

Holmes clearly hates it, but he looks to Watson for reassurance and does what Watson wants him to do, and when Watson beams, Holmes breathes a little easier and struts a little more. Robbie thinks, well, it works for them, and when you get right down to it, that's the best anyone can do.

# # #

On that day in June when everything goes so very badly so very fast, Robbie's not in on the chase, and he's glad for that at least. He's at NSY when they bring Watson in for questioning, though, and a more wrecked creature is hard to imagine. When Robbie hears about the jump off Bart's, he understands why.

Robbie's a practical man. All Dog Squad men are, but especially the ones who work with cadaver dogs. You can't be delicate and train dogs to respond to the scents of blood, of brains and guts and bone, of death. Holmes was practical too, and Robbie knows he'd have appreciated the gesture. So he calls his mate Jason, who's training up a new bitch at the Met Police Dog centre, just a pup yet but showing some talent. He says he has a site to test her responses in the field to blood and death and maybe brain matter, given the nature of the fatality. Meet him at Bart's.

Pixie's a fine young bitch with a good work ethic and a businesslike sense of purpose that all the best dogs have. When Jason asks her to find blood-scent, she goes straight to the flagstones without even putting nose to ground and assumes the blood located position, cocking her head to say, Really? You needed me for that? They laugh and Pixie gets her reward.

They check for brain-scent next. She investigates the stones, the wall, the street. She's thorough and focused, attention slipping only once when a baby with a ripe nappy goes by in a pram, which is good for her age. After fifteen minutes she's given them no positive response so they conclude Holmes' skull hadn't cracked open when he hit and call her off.

Jason tells her to find death-scent. It's the hardest one to teach; you can give a dog blood or bits of grey matter to explain what you want him to find, but explaining you want human died here is tricky. Some handlers never learn how to teach it; some dogs never learn to find it. This is a test for both Pixie and Jason.

She starts at the site of the blood-scent, smart girl that she is, but casts and casts and casts without responding. Jason makes a rookie mistake and starts getting stressed; she picks up on his tension and starts getting anxious herself, starts trying to please her handler instead of trying to find the scent. She assumes blood located position over the flagstones again, looking for approval, and before Robbie has to point it out to him, Jason realises he's being an arse and calls her off.

"She's young," Robbie tells him. "Give it time. And probably they got him indoors before it actually happened. She can't find a scent that isn't here."

Jason looks relieved and says, "Yeah, true. She's a good girl, a good, good girl." Pixie wags, Jason strokes her head, and they go back to Robbie's to drink lager and let the dogs play together. It's good for Casey to have company.

Later, though, Robbie surreptitiously checks the report and confirms that Holmes was declared dead on impact. He subsequently nudges Jason towards live tracking for Pixie—subtly, he hopes. No point in hurting anyone's pride. If Jason notices, he never mentions it.

# # #

When it becomes clear Casey's time is drawing near, Robbie arranges for two weeks off: the first to take Casey to all his favourite places and do all his favourite things and be with him all day, every day, because there's nothing that makes a dog happier than that; the second to recover from what he knows will tear his heart into pieces.

When he gets home that evening to start his leave, he finds that Casey has quietly and—he knows this is the truth—deliberately, kindly taken the matter out of Robbie's hands.

It seems ungrateful to grieve that he wasn't there to hold his friend at the end when Casey had spared him just that, but he does, because life is so damned empty without that familiar weight leaning against his knee when he sits at the breakfast table. He's been through this before, knows that eventually he'll take a breath that doesn't hurt, that eventually he won't cry when he reaches sleepily across the bed for a warmth that isn't there, but that's somewhere in the future and right now the whole world is made up of atoms that proclaim in the very foundation of existence that Casey is gone.

# # #

He's been working on the Dog Squad with his new partner for over a year when he gets a call from DI Lestrade: can he very discreetly bring Ava to St Swithin's after nightfall? Robbie's stomach sinks, because Ava's a cadaver specialist, not their best live tracker, and this means they think that missing boy was murdered.

The bundle Ava finds wedged into the high rafters is sickeningly small. Robbie takes her out to the dark car-park to throw her reward ball and tell her what a fine girl she is out of sight of Lestrade's team.

The kids are the worst. The kids are the worst and he doesn't have the luxury of getting angry. His priority is Ava.

That doesn't mean he's not fiercely, viciously glad when he sees a familiar silhouette in a posh coat striding eagerly up the stairs to the church, where he's met by the DI. Nothing in the world will bring that boy back to life, but now Robbie knows they will find the fucker who did that to him.

It's several minutes before he remembers Holmes is supposed to be dead.

# # #

There's a big splash in the news, of course, when word gets out. St Swithin's is crawling with reporters and rubberneckers the next day, making it three times as hard to search the woods for more bodies. Robbie and Ava sit quietly by the police van as the constables herd people out of the area. He strokes her ears and watches Holmes and Watson.

It's painful to see. The magnetic pull between those two is just as present as it always was, but Watson holds himself tightly apart, stiff and brittle, and Holmes—well, Holmes looks like a dog who's been kicked and starved for the last three years, desperate for kindness and scraps but no longer believing those things exist.

He wonders how a partnership rebuilds trust when it's between two humans, without a dog to be the first to forgive and just love again. He's never managed it himself, but then he's not very good with people anyway.

When they finally get to search, Ava finds two more bodies, months old, and the case becomes headline news. Holmes is all over the telly and the papers when the Met arrests the mayor's son-in-law on the basis of evidence he's unearthed.

In the explosion of controversy that follows for weeks, Robbie can't help but notice that in all the footage, Holmes keeps looking sidelong to Watson for approval and Watson stands like a man who's been mortally wounded but refuses to show it.

He thinks if he understood why this reminds him of Casey, he'd be a wiser man than he is.

# # #

In August, he meets Jason and a friend at his local for pints. When Jason excuses himself on a transparently flimsy excuse and leaves the other two there alone, Robbie realises they've been set up on a date.

Natalie's brilliant. She's smart and funny and she smells unbelievably good. Somehow they skip right over the boring so-what's-your-job type of questions and go right to the sort of things that actually matter. She makes time every year to go to a forest in Norway to see the northern lights, which is bloody fantastic, and when she persuades Robbie to tell her about the holiday he was supposed to have spent truffle hunting with pigs in France but instead ended up in a hostel in Lombardy with a pregnant, ill-tempered nanny goat and two rabbis, she laughs until she hiccups and then laughs harder.

He likes her so much he feels giddy.

"Would you," he starts, and he feels his neck flushing. "Would you like to come to supper? I've a chicken for roasting. It's just..." He swallows. In his experience, if something's going to go wrong, this is when it happens. "I need to walk my dog first."

Her lovely, lovely face pinches, lips going tight, and oh, hell, he'd really liked this one. But better to find out now—

"Robert MacIntyre," she says, "do you mean to tell me you've left your poor dog cooped up for the last two and a half hours whilst we were sat around in a bloody pub?"

And Robbie falls helplessly, hopelessly, utterly arse-over-teakettle in love.

# # #

In May, when the lease on Natalie's flat runs out, Robbie asks her to move in with him and Ava.

She tells him to ask again next year, and three weeks later she takes him to meet her parents. He's not sure, but he thinks this is a good development taken as a whole, and he's happy.

# # #

He and Natalie haven't been doing well for a while. Robbie knows a lot of that is his fault. He's not good at talking, never has been, and Natalie needs words. He tries to show her in all the ways he does know but it's not working. He's afraid to say anything these days for fear of making things even worse, but the silence is doing just as much harm, it seems. This is the most important relationship he's ever been in, he's fucking it up, and he doesn't know how to fix it.

He hates that she doesn't laugh much anymore.

Somehow he's become the handler DI Lestrade prefers to work with, which means that eventually he and Ava work on a case with Holmes again.

"We are running out of time," Holmes is snapping to Lestrade when Robbie gets there. "He wasn't killed here; that's a false trail, obviously. You need to get someone down to the wharves right away."

"Well, we'll just prove that now," Lestrade says steadily, and Robbie and Ava go to work.

They meticulously search the whole house, and when Ava finds nothing, Holmes flings up his hands and complains, "What did I say?!" as Lestrade punches at his mobile.

Robbie can't help but notice that when Holmes looks at Watson this time, Watson beams admiringly, and when the men walk together to consult with the Met team that will be searching the wharves (on overtime, God help Lestrade if Holmes is wrong), they're shoulder-to-shoulder and leaning towards each other. That's good, then. He wonders how they did it, how they found their way back to each other when they'd been so far apart with no dog to lead the way.

Even though it's dark and there's no body to find this time, out of habit he takes Ava to the most deserted spot in the area for reward-play, finds a stretch of grass for her to run on. He tosses her ball and she bounds after it joyfully. How did they do it? he wonders again. They managed somehow, and if they did it, he could too, maybe, if he just knew how. It's so much easier with dogs.

And then it occurs to him that it's not easy for dogs, is it? They have to deal with us. Which starts him thinking down an entirely new street and changes everything.

He's bad with words, but there's no possible way he could be worse at it than Holmes surely was, so that's hopeful: apparently you can do a miserable job of it and still have it work out. That takes a bit of pressure off. He can do this, he thinks, stroking Ava's muzzle with a forefinger. Even if he fucks it up a bit, they can still come out all right.

Right, then. Home. He and Natalie need to talk, and for once he feels like it might not be the verbal equivalent of a root canal. He and a wagging Ava cut through the narrow passage between buildings on the way back to the car-park and home.

It's occupied.

He backtracks quickly, as quietly as he can, but he's already seen two bodies pressed against the wall in the shadows, an elbow moving rhythmically under a long coat; he's heard the softly murmured, "I was right—oh—I was right, I was right."

Well. That's...that's...when Donovan had said...he'd honestly thought that was just a rumour.

He takes a deep breath. Right. He's not going to judge. It would be hypocritical, just the sort of thing the know-nothing dicks do to his dogs. He won't be like that.

But he's never shaking either man's hand after a case unless he knows they've been to the gents first.

You won't believe this, he imagines telling Natalie, lips twitching. He'll tell her about the detective who self-rewards, God help everyone, at crime scenes, in defiance of common sense and common decency, and how he likes the man anyway. He'll tell her, and maybe she'll wrinkle her nose and smile. Maybe she'll laugh again. It's been too long. And maybe they'll start feeling out the way back to each other even if it takes a while to get there, because the separation hurts more than the fumbling, clumsy knocks they may give each other as they try to work it out.

Because this matters, sod it, far too much to let it go without a fight, and he knows now there is a way back, even if he can't see it yet. Those two fools in the alley prove that, don't they? There is a way, there has to be, and he'll be damned if he's going to give up.

He kisses the top of Ava's head and says, "Let's go home, lovie. She'll be waiting for us."

For Jack and Megan, who loved as only they could.