Disclaimer: Nothing you recognize is mine, as usual.

A.N. I mention Sir Henry Merrivale, creation of Carter Dickson – alias of John Dickson Carr – in here. Not only because of his competence (Gideon Fell or Bencolin would have worked as well). One of Merrivale's many nicknames (H.M. and Old Man among others) was, according to the Plague Court Murders, Mycroft. Not that H.M. liked it at all, and I think Mycroft would strongly object to the comparison too, but I couldn't help myself.

Revenant

Sergeant Sally Donovan was not a woman who regretted many things. After all, remorse alone didn't accomplish anything. If you could put to right what you messed up, you better do that instead, and quickly. If you couldn't...As long as you didn't repeat the same mistake (but she knew better than be so stupid) the best thing was to go on with your life and don't ruin it dwelling on what was in the past.

Today though, pouring for the nth time over the documents of the Adair case, she felt decidedly incline to wallow in regret instead. It was all useless anyway. A locked room murder. They had on their hands a proper locked room murder straight out of Carter Dickson. How were they supposed to solve that? What did the press (because of course that had made all the titles, secrecy of the investigation be damned) expect them to do? Find a self-teleporting murderer? She would like nothing better, but there were no clues after all. Anderson (poor, so very under-appreciated Mark) and his squad had combed through the room and come out empty-handed.

Which was exactly why Sally was so dejected today. Even Carter Dickson didn't expect the police to solve impossible murders, that's why that oddball Merrivale was around. But they had no Merrivale, and no...no one anymore able to solve this. She maintained that Lestrade had called the Freak too often. To keep him entertained and off drugs, she suspected, but they were the police; they shouldn't take on bloody charity cases! It was in the one-in-a-million chance something like this happened that a consultant (even an unbearable one) was seriously needed.

And it was her fault he wasn't around to spout that it was obviously the sister, because the dust had been disturbed...or something equally as insensate when you first heard it. She had never wanted that, really. She wouldn't wish that on anyone. She had felt a cruel glee at being finally proved right and seeing him in disgrace though. Only she wasn't right. She'd been duped (like everyone else, but that didn't make it sting any less). No, not like everyone else, but John didn't count. He wouldn't believe it even if the Freak had really indulged in serial killing like she had always expected he would – come on, he was rapturous over those. Anyhow, subsequent investigations had – recently – proved beyond any doubt Moriarty was real, as the odd graffiti appearing here and there said from the start. Way to go, Sally. Used by a criminal mastermind to get rid of the one person as freakishly brilliant (she was right; John too) you had on your side, and now with another impossible killer on your hands.

A sudden scream made her look up in alarm. She didn't, though. No screaming, no running, no nothing, and she was pretty proud of that. Because there was a ghost inside New Scotland Yard, and it wasn't even Halloween. A long legged, curly haired ghost who walked in as if he owned the place. As usual. There were a few differences...well, that was to be expected. No coat, for one (she didn't know why that surprised her). And he was even more gaunt that he'd been before. Sally was just grateful he wasn't spookier, you know, with his brain leaking out from the fractured skull or something of the sort. She'd surely lose her lunch over such a scene. Probably too vain to go around like that, even as an apparition. She couldn't drag her eyes away from him. He was coming forward, towards her, like Banquo's bloody spectre (not that she'd planned his death, but still guilt lay heavily on her), and nobody would stop him. Of course nobody would. Everyone was doing his or her best to stay out of that thing's way, and she couldn't blame them.

The timing was off, though. It didn't surprise her that the Freak would haunt Scotland Yard. Either to take some form of revenge – though she desperately hoped this wasn't the case – or to assert his superiority as usual, pointing out just how inadequate they were, or maybe simply because afterlife bore him. Having Sherlock's ghost messing up their cold cases' files should have been an acquired habit by now. Instead nothing, until now – three whole years after the...event.

Sherlock had started talking by now (so he could), his words rumbling out the way she remembered. No sepulchral effects added. "I shouldn't even be here," he said. Everyone in the room would whole-heartedly agree with him on this, but nobody breathed a word. "But you can't be expected to solve this on your own, can you? It was right before your eyes the whole time, and you didn't realize. Adapted the facts to your theory as usual – and I can't really understand why, since your so called theory didn't even leave you with a scapegoat at hand this time. It left you with an impossibility, in fact."

It was then that Sally found enlightenment. She resolutely ignored the jab – she had a lot of practice on doing exactly that – and latched on whatever was significant. The Adair case! The Freak was back from his grave to solve the Adair case. She should have known. How many times had he reproached Lestrade for calling him about 'simple' crimes? How many times had he refused to leave the flat over something he deemed beneath himself? Never understanding Lestrade had his consultant's frail sanity at heart when he asked his presence for something they could have – should have – solved themselves. Even if they hadn't closed every case they had in the past three years (God knows they didn't), his ghost had slept soundly. Or played the violin on a fluffy white cloud. Or done whatever. They faced a locked room now. That had to be at least a nine on the Freak's scale, right? And his ghost was here, because nothing trivial like simply being dead would stop Sherlock Holmes from meddling with it. It was a wonder he hadn't turned up at the crime scene. Did ghosts get some sort of transmission delay?

She was so entranced by the apparition that she didn't notice Lestrade coming out of his office until he casually swept the Adair files out of her hands.

"Sherlock," the DI said, "it's fine if you want to discuss the Adair case – or any other case, really – but come with me, will you? We've been doing our best, and nobody here needs your insults. See? I've got the documents".

His voice was perfectly steady, and Sally's admiration for him skyrocketed. He'd pretty much just baited a...ghost? Zombie? The Freak looked awfully solid to her, to be honest. Anyway, Lestrade had lured a preternatural creature into a tight, closed space, and Sally really really hoped her superior had a plan beyond sitting with him and listening to his deductions. Or knowledge on dealing with this, improbable as it was. She seriously doubted this was covered in the refresher course Lestrade had been to last month; especially because he came back, well...particularly refreshed. If the DI's ideas of how to treat your undead (walking dead? What?) consultant were based – like hers – on TV shows (Supernatural anyone?) she could only hope the screenwriters had done a bloody well accurate job researching. She was going to personally sue them if things went sour. Of course assuming she'd survive that.

Sherlock had followed Lestrade to his room. Of course he had. Crime scene photos and other investigation files were for him essentially what a baby goat was for a tiger. Or blood in the water for a shark. The perfect enticement. Which should have said things about the Freak. The things she used to say aloud. The consultant passed by her desk – not a glance spared to her. Sally decided she'd be daring. Couldn't stay in Lestrade's team if she was a coward, could she now? Especially after he handled the whole thing so nonchalantly. So she let a finger of hers brush against the dead man's hand. She was curious if he really was as solid as he looked. What she found out startled a gasp out of her. Not that it deserved more than an eye-roll from the bloody Freak before he shut the door behind him, the DI already back inside his office.

"He's alive!" she announced loudly. "The bloody bastard – he's got body heat. He has to be alive!"

"But he was dead, wasn't he? How the fuck did he manage to fake falling to his death? In front of a doctor – ok, scratch that, John wouldn't out him – though someone has to nominate Watson for the Best Supporting Actor Oscar," a colleague ranted.

"Maybe he was dead? All the time? Like – you know – a vampire? That'd make things easy," another one offered.

"And that's what you get for being young, impressionable and living near Highgate cemetery in the 1970s. No Violet, he isn't. But he sure as hell will have to explain a lot of things beyond who and how killed the victim this time. At least I hope so," Sally bit back. She really, really hoped.

P.S. In the 1970s, a vampire was allegedly sighted in Highgate cemetery in London. Two men, Sean Manchester and David Farrant, tried to exorcise him and managed to get quite a bit of publicity with their rivalry. It's an highly amusing tale.