Author's note: Happy Halloween! I had this planned for some time. Explanations after the story.

I don't own anything, please review.

John Watson has seen many expressions on Sherlock Holmes' face. He has seen him smirk, he has seen him laugh, he has even seen him cry. He has seen him apologetic and doubtful if the doctor would welcome him back into his life after he returned from the dead. He had seen the relief in his eyes after he'd first hit and then hugged and told him never to leave again.

But during the last few weeks, he has now and then caught glimpses of an expression on Sherlock's face he's never seen before. Or at least he doesn't think he has seen it there before; he can't deny that it looks strangely familiar, and he hasn't seen the expression long enough yet to try and comprehend what it means. He only catches it in reflections or moments where Sherlock thinks he isn't looking at him; and once the consulting detective realizes John can see his face (he always does) he immediately schools his features into the blank mask the doctor sees so rarely these days.

And that alone is enough to tell him something is wrong.

Sherlock has been back for over two years now, and he hasn't lied to John since he came back. Then again, he hasn't lied to John. Not exactly. But he isn't telling him what is troubling him either, and it makes John shudder to remember the last time that happened.

Moriarty.

He tries to be reasonable; certainly, if Moriarty had survived, they would know about it by now, and if someone as dangerous as the consulting criminal showed up – if someone took his place – Sherlock would tell him.

Which means –

Which means this, whatever it is, could be much, much worse than the consulting criminal.

At first, he tried to tell himself that it was nothing, that he was simply being paranoid.

But now – it's not only the expression on Sherlock's face when he thinks no one is looking. He acts less excited on cases, he doesn't do as many experiments as he used to, and he doesn't play his violin at all hours of the day.

In fact, that is what is troubling John the most.

Sherlock has gone so quiet.

He still talks, of course, but there are no explosions, no concertos in the middle of the night, no –

There used to be a stir in the air when Sherlock was home, almost like an electric current travelling through the flat, that told John he was there.

It's gone now, and that scares the doctor more than it should. Sometimes he wakes up in the night, and the flat is so still, so utterly still, and the silence is more deafening than any of the noises Sherlock makes when he is bored, and –

And it is as if Sherlock hasn't come back. As if John had dreamed that he suddenly stood in front of him two years ago, demanding his help on a case and begging him through a haunted look in his eyes to come back to the life they had known before.

John isn't ashamed to admit that he sneaks down on nights like these under the pretence of making tea. Usually he finds Sherlock awake – silent, but alive – and it helps him go back to sleep.

Still, something is wrong.

And John will find out what. He can't stand the silence, and he can't stand Sherlock keeping secrets from him, not after –

Not after what happened the last time he did.

John has had enough. He's going to talk to Sherlock tonight.

They are between cases, but Sherlock has been busy with an experiment, so apart from whatever it is that is troubling him, he is in a fairly good mood, so that asking him what is wrong might turn out easier than John hoped. Then again, who can tell when Sherlock Holmes is the one keeping the secret.

He enters the kitchen and puts the kettle on. Sherlock is looking through his microscope, but John can tell he is aware that the doctor wants to ask him something. Still, the consulting detective doesn't acknowledge his presence.

John clears his throat. He isn't sure if Sherlock will continue to ignore him, if he will try to prevent this conversation, but his best friend looks up from the sample he has been studying and musters him with well-practiced indifference.

Only that John know, of all people, that Sherlock isn't indifferent towards him, and that his face only ever takes this expression when he's looking at the doctor because he is hoping to get him to stop.

But John is determined, and he can tell Sherlock sees it because an almost imperceptible sigh escapes the consulting detective.

The doctor starts with, "I made tea" and immediately knows he was right that something's bothering Sherlock because his best friend doesn't answer "Obviously".

"Let's go drink it in the living room" he continues, because he can tell this will be a longer conversation and he doesn't want to give Sherlock the opportunity to hide behind the microscope again.

Sherlock complies.

He doesn't say anything once they're seated, though, and John is really worried now.

"Sherlock?" he asks, and that one word holds so much meaning, like it has so many times before. This time, he is begging his friend to tell him what's wrong.

Sherlock takes a sip of his tea, and John can easily tell that he's pondering whether or not to tell him.

Finally, he takes a deep breath and announces, "Mr. Chatterjee is dead".

This is a rather unexpected reply – even from Sherlock Holmes – and John needs a moment to remember that Mrs. Hudson's old beau (they apparently got on better during his last few weeks once again, but she hasn't shown any signs of grief, so he figures Sherlock can't be concerned for her) died about two weeks ago.

John waits for Sherlock to continue, but the consulting detective never does.

He looks at his best friend, who is pointedly looking anywhere but at him, and then he understands.

Sherlock isn't concerned for Mrs. Hudson because she isn't sad about the man's passing. He is, however, worried about something. Mr. Chatterjee died of a heart attack, as far as John knows, but that doesn't mean there is no foul play involved – but, if there was, Sherlock would be excited, happy about a new case.

Unless –

Unless he already knew.

Maybe he already does.

And he desperately wishes he didn't.

And that means that, if there is a case, and he does know, and he is on edge because he does –

The killer is someone he knows. Someone he cares about.

And that means –

John forces himself to relax.

"Do you – " he swallows, because Sherlock being so bored that he sees a crime everywhere is the only explanation. Because Mrs. Hudson wouldn't do something like that.

"He had another wife in Brighton" Sherlock replies, and even though this whole situation is so utterly strange, John can't help but appreciate how well they understand each other. Sherlock knows he knows what the consulting detective thinks. They don't need to explain.

John wants to protest, but then he looks into Sherlock's eyes and sees dejection, the expectation that the doctor, his blogger, won't believe him, and he can't.

Instead, he asks, "When did you first – "

"Her husband was a serial killer" Sherlock explains, "but I never suspected her. Of course, the money she eventually bought this house with came from an old man she took care after her husband had been executed. Later, she told me about a woman she had looked after while Mr. Hudson had still been alive and who had died of cancer – again leaving some money to her. I – "

Sherlock breaks off, then forces himself to continue.

"I am afraid that I didn't consider all possibilities".

John almost laughs amidst all the craziness, because Sherlock Holmes admitting that he didn't eliminate all possibilities is unheard of.

"And Mr. Chatterjee?" he asks, afraid of the answer, even though he tries to convince himself that Sherlock can't be right.

He is talking about Mrs. Hudson. The landlady who has treated him like her own son ever since he moved in. The woman who has treated Sherlock like her own son since she met him in Florida.

"He was healthy. He went on a morning run every day. And he had tea with Mrs. Hudson two hours before he died".

"I – Sherlock, I can't – "

"Believe me?" The consulting detective sounds angry and bitter, and John can't tell if he sounds that way because of John's doubts or his disgust at his theory.

"Not that I am surprised" he continues, calm, too calm, and John shakes his head.

"Sherlock, do you have proof?"

Sherlock looks away, and John's heart drops.

"I will have" he replies curtly. "Mr. Chatterjee donated his body to science. It was taken to the morgue. Molly is making tests as we speak."

John nods, once, twice.

He knows he should tell Sherlock that he must be mistaken. But he can't.

Because this is Sherlock Holmes, and he has been solving crimes for years.

"So we wait" he says, and his best friend nods.

They wait.

Until the door opens and Mrs. Hudson shuffles inside, carrying a tray.

"Hello, boys, I thought you could need a cuppa and some biscuits".

John stares at her, thoughts racing through his head, his heart beating.

Then he hears Sherlock huff and realizes he's supposed to act like nothing is the matter.

He smiles. "Mrs. Hudson, you are a saint."

She gives them both a cup and sits down in Sherlock's chair.

Sherlock nudges John with his knee, and the doctor takes it for the warning it is.

He pretends to take a sip and asks, "And how are you today, Mrs. Hudson?"

"Oh, my hip is troubling me again, dear, but other than that – "

"We know about Mr. Chatterjee".

John looks at Sherlock. He didn't expect that. Sherlock may be blunt, but to tell Mrs. Hudson straight away, even though he know if he's wrong he might hurt her –

On the other hand – she was one of the three people Sherlock faked his suicide for, one of the reasons he spent three years alone hunting down Moriarty's web.

And Sherlock asked Molly to do the tests. Sherlock didn't want to see the proof of what he already knows himself. But Sherlock couldn't sit there, drinking tea with her quietly, either.

Mrs. Hudson's smile doesn't falter, and John can't say if this makes it better or worse.

"I can see you won't believe me if I deny it. He had another wife, you know. And I thought he was finally ready to commit". She pauses for a moment. Then she takes a large gulp of her tea, and John understands immediately what she is doing.

He wants to stop her, but Sherlock's hand on his arm tells him he shouldn't.

"It wasn't the first time, you know" she continues pleasantly, "and if Sherlock hadn't shown up when he did, my husband would have been the next. Just to make it easier for him, of course – he was a good man. Despite his problems".

She looks at her watch.

"Oh dear me. It's getting late. Goodbye, my boys".

She leaves, carrying the tray, and already starting to sway a little, and John sits still until he hears the door to her flat close.

"And now?" he asks quietly.

Sherlock simply answers, in a tone that tells the doctor of finality and pain, and makes him realize that the consulting detective wanted their landlady to make this choice, to pass on as a respected and well-loved woman, "We wait."

So they do.

Author's note: Last Halloween, I turned Lestrade into a serial killer, and I couldn't resist. If you'll excuse me now, I'll be hiding in the corner.

This ended up different than I thought it would – oh well. What else is new.

I am now posting my fanfictions on AO3 as well – I will revise and partially rewrite my older stories while reposting them there. In case you are interested after what I just put you through, the address is:

/users/Hekate1308

Have a wonderful Halloween!