They walk back with Violet to the house. In the vaguest sort of way, Sherlock wishes John would just go back to the pub, leave them to it. Normally nothing would stop him telling him so. Something about today makes him hold his tongue. He settles at an expression of mild shame, not unlike Violet's. At least he doesn't hold himself when he walks the way she does, as though there were more than a warm summer breeze cutting through her jacket.

The gate at the bottom of the driveway isn't tall, but is nonetheless chained and padlocked. While Violet opens it with a borrowed key, filling a gap in conversation – "You get to go through this time," John says, "rather than over."

Is that a joke? It can be rather hard to tell. Certainly he's smiling, looking pretty bloody pleased with himself.

Sherlock doesn't answer. Violet pretends not to have heard, and when she walks on again, Sherlock falls into step with her. "Do you remember Ruby?" she asks. The question breaks from her. It's preyed on her mind and here at the end of their walk it's now or never. "Ginger Ruby. Her dad was a big…" 'Dealer'. The word is 'dealer'. Instead, she casts a wary glance at John.

"Yes, I remember."

"Ruby's dead. I felt like I should tell you. She used to talk about you all the time."

Determinedly lifting his voice, open, inclusive, "Overdose?"

"Nah. She was high as a kite and thought she could walk along the rail down at the river. You know, just there where the south bank is dead South Bank? She hit her head before she hit the water, never came back up. I was there. Anyway, I just felt like I should tell you."

He nods. For whatever reason, says, "Thank you."

"Listen, I'm going to have to slip back in the back door. I don't have the key for the front. Carlo's back there so-" His brow had furrowed, "-The dog. It's named after a football player. So you should probably…"

"Avoid. Yes. But Violet, before you go, you're absolutely sure there's no one else in the house?"

"Totally. Mr Rucastle's never even mentioned he has a daughter. She doesn't live here anymore."

He lets her go then. And watches her go. He'll stand right where he is until he sees her through one of the front windows, safely inside. Or at least until he hears the closing of the door and knows she's past Carlo. John steps up next to him. Only once he's close does Sherlock realize how respectful his distance was. He gave them their space, he let them talk. And now he's worried. Because what do Sherlock and Violet share, what makes them them, and John something separate? It's with not a little suspicion that he waits for John to speak.

"That's it? We're just walking off? I thought we brought her back so she could let us in."

"While I am not entirely averse to breaking and entering, where it might serve to further the pursuit of the truth, I'd rather not try it at the home of a former Detective Inspector and his canine defender. Especially not when it's going to be so easy to gain legal access."

"How?"

"If you're in the pub around seven-thirty tonight, you'll see." John grimaces. Hates little turns like that. He feels like he's being fobbed off. It wouldn't be polite, or even nice, to twist the knife. "Really, you'll kick yourself. It's not even very clever."

"Well, that, I definitely don't believe."

"I did say 'very', didn't I? It's still clever."

"Yeah, that sounds a bit more you." That puts something of a smile back on their faces. It gets them, at least, as far as the end of the drive. Then Sherlock has to stop, to close the padlock back on the gate. It's instinct rather than any sort of fear that makes him draw his hands back into his sleeves, shielding his fingerprints. While he does it, John stands behind him, watching the road. It's quiet here, private. Here at the beginning of the trees, Rucastle's is the only turning. They're alone, and Violet is far from them. "I'm sorry," John says.

Hesitating, trying to clarify, "About what?"

"Violet. I know you… Well, no. I don't know what you thought, not really. But I know you were hopeful and-"

"What are you talking about?"

John stares, for just a moment. That gormless look on his face, like when he's about to say something he knows will turn out to be stupid. It feels like the only answer to him now, but in a second, Sherlock is going to turn it on its head. He's sure of that. But for once, he can't even imagine what might be coming. Another moment of the stare is disbelief. Then John looks back toward the house, lifts his open hand to show what he means, "It's obvious, isn't it? Sherlock, there's no way she's clean."

Anger swells, and blossoms, and is squeezed to pop in under a second. Calm as he knows how to be, "Yes, she is."

"Well, maybe if you don't actually look at her."

"Not to put too fine a point on it, but which of us is better qualified to know if someone is using or not?"

"The trained medical professional."

"Fine. In your professionally trained medical opinion, what's the proof?"

John makes a list. It is extensive and comes very easily to him. This is what Sherlock saw on his face in the café. He was picking these things out, lining them up for later on. 'Long sleeves' are on the list, in which case both of them and everyone they've so much as passed today is a suspected addict. The small scab on the side of her face, which may well be the last remnant of a much larger problem, is on the list. Incoherent speech, paranoia, the jerky alertness, that's when Sherlock feels the needs to interrupt. "Also symptoms of fear and anxiety."

Still listing, undeterred, "She walked like her hands and feet were made of lead."

"Naturally. She was standing in a window at half-three this morning…"

"Alright then. No laces in her shoes." No. Sherlock noticed that too. There were safety pins holding either side of the upper to the tongue, but no laces.

"You get very observant," Sherlock mutters, "when you're looking for faults."

"No laces. Refute that. Weren't you the one who told me what that means?"

It means she used them for tourniquets. What it doesn't mean, is that she did it lately. "Old shoes."

"No they weren't. And even I saw that. I don't know what's worse. The idea of you lying about it, or the idea of you not noticing…"

Don't think you're smart. You're not smart, and certainly not smart enough to tell me what I'm supposedly missing.

The things Sherlock wants to say are cruel to both of them, and will take them into too-cruel territory. What he intends to do instead is walk away. He will leave John to his own devices until he is ready to accept that he is wrong. His observations are correct, but his conclusions are far from it. When he is willing to be counselled, to hear that there are alternative explanations to the one he so adamantly believes, Sherlock will be waiting. For now, he needs to get away from here, out of sharing space with him.

He is tossing up whether or not to formally excuse himself, and glances to check his exit, following the road deeper into the woods.

Someone is coming toward them. Another farmer, perhaps. Certainly the same boots. Younger, though. Weather-worn, but not yet tanned to leather. Scarred across the hands and arms, and with one small nick by the corner of his eyes. Someone's hired help. Walking fast but not out of breath yet; he only picked up speed when they came into sight. Headed straight for them. John sees Sherlock looking and the argument ends. "What's happening?"

"One way to find out," Sherlock mutters. Lifts his voice, and his face to show he's listening, "Hello?"

The young man points at Rucastle's house. Arm straight, strong, and not being delicate. He tips his head and there's a glitter of little flashes from his ear; a long bar from edge to edge, two studs caught in the inside curve. "Were you up there?"

That's all he wants to know. He wants to know it now and with great urgency, but it's all he's asking. John is cagy but Sherlock answers, as quick as he knows the answer is wanted, "Yes."

"Is she there? Is she there now? I don't care about the fucking dog, I'll take the fucking dog; is Alice up there? Alice Rucastle. Small, brown eyes-"

"No. Alice doesn't live here anymore."

"She does," the farmhand insists. Turns his open hand into a fist, so tight it shakes, juddering in the air like the moment a punch lands, trapped in that little violence. "He told me that too, but she does. She wouldn't have gone anywhere and not said something."

John steps forward to intervene. "There are two people living there," he explains. Sherlock finds his gaze drifting back to the odd, staggered building on the hill. In one of the front windows, a curtain flutters down to hang straight. Violet was peering from behind it. Why are the curtains drawn in the daytime? "One of them," John is saying, "is Mr Rucastle-"

"-Yeah, the lying prick."

"-And the other is his live-in… help. Neither of them is called Alice." If seeing them had given him any hope, the young man loses it now. He gives up on them, waves them off as part of the conspiracy. He shoves past John muttering about lies and liars and keeps on down the path towards town. John turns to Sherlock, "What was that?"

"Proof." His own plan hasn't changed. Sherlock turns in the other direction, content to leave John standing there alone. "Proof," he calls back, "that whatever you think of Violet Hunter, we've still got work to do here."

Sounding almost bored, "Where are you going?"

Too soft, not wanting him to hear, "To shoot up…"

"So the pub, then? Half past seven?"

"Yes."