Title: Bookworms Anonymous; a Sherlock and Black Books crossover

Author: Dayja

Summary: Sherlock has a friend. Well acquaintance. Well family and/or love interest. No, more like…well…Sherlock has a something. Someone. It's one mystery that John's dying to solve…until the mystery turns much more sinister when Bernard Black is kidnapped and Sherlock takes the case.

Rating: teen

Warnings: the ridiculous intermixed with angst, drama, science. Probable violence and blood. For the moment it's a work-in-progress but I hope that to change soon. More warnings may be applied as needed.

Disclaimer: I do not own/am not associated with/make no money from BBC's Sherlock or Black Books. I am associated with books by Mir Foote which can be found at amazon or her website (mirfoote dot com). Sherlock or Black Books can also be found at Amazon, among other places, but not at Mir Foote's website as she is not associated with them either.

1.

"What is that?" John demanded, staring at the specimen Sherlock had laid out on the kitchen table with a mixture of horror and curiosity. Horror because it would never cease to be horrifying to come home to Sherlock dissecting a creature that looked part rat and part lizard in the place John was intending to prepare some food. Curiosity because John was a military doctor and weird though the creature was, it wasn't really on the same level of awfulness as a once human being that's been torn apart. He could accept it as a fascinating example of…whatever it was.

"I believe it to be an evolved sort of book worm," Sherlock answered as he poked delicately around vicious looking teeth before slicing into fiercely scalded skin which was an ugly blistered mixture of scale and fur.

"Seriously?" John demanded, "That is like no worm I've ever seen."

"That would be because the term 'book worm' is a misnomer as the species is, in fact, part of the coleopteran family."

To that statement, all Sherlock received was a blank stare.

"That means beetles, John."

"Right. I repeat…that is not an insect of any kind."

"It has six appendages and an exoskeleton," Sherlock answered, impatiently pulling at what John had thought was charred skin but on closer inspection consisted of fused black ridges. And once he got past its rat-like head he finally saw that it did, indeed, have four legs and two arms.

"I see…" John said, "And you found this mutated book worm…"

"In a book shop," Sherlock answered, his tone implying that to be the only obvious place to find such a specimen.

"In a book shop…and you decided to dissect it…on our kitchen table. Is this…for a case?"

"Biology may not be my study of choice but the implications of an evolving micro-ecosystem are too important to ignore."

"So you were just bored then. Wait…are there more of those things wandering around a book shop somewhere?"

"Regrettably, there is reason to believe the species is now extinct as the owner of the book shop and his assistant thoughtlessly had them stabbed, crushed, and, in this case, boiled the last remaining female."

Then Sherlock continued his study of the specimen and John reconsidered what to do for dinner. And if it took him nearly two months to go near a book store or to open a book without flinching, well, Sherlock had taken to making John do all the book reading, relying solely on the internet for his own research, and so seemed disinclined to comment. New mutated book worms failed to show up, though there was a time when Sherlock seemed to always have some crustacean or other on display, until cases picked up and the biological studies were put aside for severed fingers and vials of something that fizzed and exuded the rather unlikely smell of mint. Life went on.

It was about three months later that John first began to notice the phone calls. Presumably they had been happening all along, but it wasn't until Sherlock cut off mid-exposition to answer his mobile that John first took note.

John watched in disbelief as Sherlock paused in his condescending rant about left shoes and torn photos to reach into his pocked, glance at his mobile's caller ID, and then held up an apologetic finger that was universally accepted as a signal for 'one second, I have to take this', before he accepted the call.

"Yes?...No, I'm quite certain he's classified as human…for the last time, I am not going to dissect your assistant just to be certain…Ber…no…no…"

"Excuse me!" the large wide-eyed man at John's back who Sherlock had accused of murder demanded, his knife still pressing into John's neck, "I really will do it!"

Sherlock shot him an annoyed look, holding up his finger in a 'in a moment' gesture once more and the thug holding John hostage actually stammered out a 'sorry', the knife edge scraping lightly against John's throat.

"Well did you try looking to the left?" Sherlock asked the mysterious person on the other end of the line, "...Well then what about the right?...yes, it is a mystery how it got on your desk, in your direct line of sight. I'm going to hang up now." And he did, finally offering his attention back to the scene on hand. "Right…where was I?"

"You were saying how he murdered that girl," John offered helpfully while Lestrade and the other officers on the scene just stared in flabbergasted horror.

"Right…no…I was saying how he killed that girl. He isn't a murderer."

"I am!" the knife wielding maniac screamed back, "And if you push me, I'll gut this…"

"Oh enough!" Sherlock screamed right back, "John, will you put an end to this farce already?!"

"What?" asked the knife wielder, "My name isn't…" Which is around the time John's elbow met his stomach even as his other arm twisted his wrist sending the would-be murderer tumbling with a painful and surprised 'oof' to the ground while his knife clattered harmlessly away in the other direction.

"As I was saying, Ellie's death was an accident," Sherlock said as officers swarmed over the downed man, "This man's an idiot but he's mostly harmless. Come along, John, I want to see how the fingers are progressing."

"Right," John murmured, his own fingers pressing to where a thin trickle of blood ran down his neck, "So who was that on the phone?"

But Sherlock didn't answer as he had already gotten in a cab and John only just managed to jump in himself before it raced away, Lestrade calling uselessly after them about paperwork.

After that incidence, John took more notice of Sherlock's phone calls. And they were calls; as far as he could tell the mystery person never texted and Sherlock never texted them in return. And Sherlock always answered. Always. Sherlock only sometimes bothered to answer when John was calling him, and John might reasonably get into actual danger and be calling for help. As far as he could tell, whoever was calling was most often concerned with the mystery of his missing wine, and the times when the caller seemed to be in actual distress, Sherlock's usual response was 'have you been drinking absinthe again?'.

Eventually, in a fit of boredom during a lull in cases which Sherlock had first spent desolately on the couch refusing to respond to anything until the mystery person called, at which point Sherlock became unexpectedly animated as he argued with the person on the other end whether the dinosaurs from some obscure book by some obscure Victorian writer had escaped the book's pages to live in someone's beard…well, while this phone call was going on a rather bored John decided to make a chart. He felt very Sherlockian as he puzzled out the bits and pieces surrounding the mysterious caller and wrote them all down in a list. The clues were as follows:

1. Caller was probably a man. From what little John had managed to overhear, the caller's voice sounded male. And Irish. And often loud.

2. Caller either did not have a mobile, had a mobile that didn't do texting, or was illiterate and/or hopeless with technology. Sherlock was surprisingly accepting of this, never berating the caller about their old fashioned means of communication.

3. Caller had a friend/assistant/relationship with another man who was hairy. This man's hair bothered caller. At least John hoped it was a man.

4. Caller was not Sherlock's friend. At least, Sherlock did not classify him as a friend. Though John would count many among Sherlock's 'friends', Sherlock himself had his own classification system as follows:

Acquaintance: Anyone he met at any point and bothered to remember who falls into no other category. Actually, considering he doesn't often remember anyone he has no use for, this could just as well be labeled 'temporary acquaintance until said person is deleted from memory'.

Informant: homeless network, Scotland Yard

Tool and/or experimental subject: Molly, John, Lestrade, Scotland Yard, anyone willing to put up with him or give him things, often the latter being pleased former clients

Client: …clients.

Impediment: Anderson, Scotland Yard, informants who refuse to inform, lesser unarmed villains, boring clients

Enemy: Mycroft, Moriarty, armed villains, Scotland Yard, Irene

Puzzle: Interesting clients, Moriarty, Irene

Family: Mycroft, Mrs. Hudson, Lestrade

Friend: John

So…not a friend. Perhaps he's family? Or an enemy. Each seems equally as likely with Sherlock.

5. Caller and Sherlock argue about wine, books, a hairy man, and weird creatures.

It was as John was writing down point number five that his brain finally made a few connections that Sherlock would probably have noted straight off, if their positions were reversed.

"He isn't…he isn't the one who gave you that…that…book worm is he? He's the book seller. He's the book seller with his own evolving micro-ecosystem." Sherlock didn't bother to respond, still curled up on the sofa and listening to whatever the caller on the other end was saying, but John was still quite certain that he was right. He wrote that last bit down on his chart. Then he sighed in utter boredom, crumpled it up, and went to see what was on the TV.

He had a brief moment to catch sight of some children's show featuring a giant puppet worm with glasses coming out of a book before he shrieked and turned it off again. Sherlock sent him a glare.

"Sorry," Sherlock said into the phone, "I didn't quite catch that, my man was being noisy again." Or perhaps he said 'my manny'…John wasn't sure and in either case it didn't make much sense anyway.

"Right," John said, "I'm going out." Maybe that girl he met at the pub last week would be interested. Sherlock ignored him and went on with his conversation.

Later, which turned out to be the morning after he awoke in his date's tiny flat, he came home in rather a good mood to find the list he had made un-crumpled and viciously edited with scathing comments and corrections. Mycroft, for instance, was decidedly crossed off the family category, generalizations were replaced with ridiculously long lists of actual names, John's own name had unexpectedly been added to both 'puzzle' and 'family', while the above numbered notes were marked with 'yes', 'landline. Sometimes.', 'yes', 'Pointless categorization, and you forgot 'love interest', and 'finally'. John's brain had stuttered for a moment when he got to the 'love interest' bit, but Sherlock had not deigned to actual put any names next to it so John decided it probably wasn't important. The final point simply said, 'yes'. So the mystery caller was a book seller. He still didn't have his name, or any information of real use, but at least that was something. At the very bottom was the instructions 'burn this'. Feeling a bit rebellious, John hid it away in his underwear drawer instead. Later, he found his pants covered in fine ash. The mystery of who the man was continued.

Finally, after one of Sherlock's brief two second calls ('Yes? Look under the bath. Click), John asked outright, "So…who was that then?"

"You know who," Sherlock answered with a raised eyebrow, "You did a list and everything."

"Are you talking to Voldemort now?" asked Molly as they stood over the dead body, her voice angling for humor and inclusion in their conversation. Sherlock gave her an utterly blank look and she quickly went back to showing him the way the slash marks cut through the bones.

"So…where is this book shop anyway?" John tried later, "Shouldn't you be checking up on its ecosystem?"

"You were doing so well with your deductions. I wouldn't want to deprive you," Sherlock answered lazily while fiddling with John's laptop. Before John could press him for more, Sherlock suddenly slapped the laptop shut and jumped up.

"Where are you going, then?" John asked as Sherlock ran around looking for his tie.

"Concert," Sherlock answered abruptly, "A rare performance; business must be slow if he was allowed out. I hear he's playing Bach tonight. You could come too; bring that date of yours."

"I don't think music is really her thing," John answered hastily, still remembering the last time he had taken Sherlock's advice on dating. He had no intentions of ending the night being kidnapped.

"Suit yourself," Sherlock answered before running out.

It was around then that John developed a bit of an interest in book shops. It wasn't a conscious decision; he never sat down one day and decided he'd find Sherlock's book shop if he had to search ever shop in London. He wasn't even sure if the man Sherlock talked to actually lived in London; for all he knew Sherlock was talking to someone living in Australia or China. But whenever he did happen upon a book shop, he had started going in. His collection of books, which had rather dwindled after the book worm incident, was now beginning to pile up. It looked like he might need a new bookcase soon.

Still, despite dwindling book space and Sherlock's occasionally remark, it was only when John insisted on diving into a random book shop during the middle of a case, purportedly because he hadn't eaten all day and the place advertised coffee and muffins, that John realized he was developing a bit of a book shop addiction. Particularly as the first thing that crossed John's mind when he stepped into the shop was, 'there's no way this is the place'. The shop was clean, almost robotically sterile, with neat displays and automated help desks. There was no way to imagine escaped book worms or dinosaurs or missing wine bottles in a place like that. There was no way to imagine anything going missing; it was the sort of place where everything was catalogued and orderly and the only drinking going on was in the designated drinking area and even then it was all coffee. John took one look around the soulless store and almost turned right back around, muffin or no muffin.

He caught himself before he did and recognized that he had a problem. In the end he did get his muffin and a coffee, paying a ridiculous fee for some machines to make his food so the faceless worker could do his job of handing it to him. If it weren't for the fact that John was quite certain science had not advanced that much, John would have suspected that even he was a robot. As it was, he thanked him politely and went back out to the pavement where Sherlock was impatiently waiting. Luckily, he was doing something on his phone to distract him or John would likely have come out to find he had already gone.

"I got you a muffin," John offered, brandishing it in Sherlock's face in the hope that the smell alone would remind the man he hadn't eaten all day and that Sherlock wasn't a robot either.

"On a case," was all Sherlock mumbled, leaving John to eat the muffin himself. John did note, as they started on again, that there was a second bookstore right next door, but he managed to steel himself against such foolishness and didn't even try to go in. As if he could find a single book shop by entering every single one he laid eyes on anyway. After that, he tried to reduce his book buying to no more than once a week, and even then to go to places he already knew.

So Sherlock never did tell John who the caller was. John even tried asking people like Lestrade and Molly who had known Sherlock for longer, but they were just as baffled that anyone both knew Sherlock well enough to call him on a regular basis and liked Sherlock well enough to call him on a regular basis. That Sherlock continuously put up with him was an even great mystery, and one that it looked like would never be answered. Until the day Sherlock's phone went off when John was next to it.

"John, phone!" Sherlock mumbled into the sofa where he had lodged himself during one of his darker fits that John had seen. John glanced at the caller ID but all that was displayed was a number. John answered anyway, something like a thrill of hope passing through him as he realized who the caller might be.

"Hello?"

The response was unintelligible yelling into his ear. John jerked the phone away, before cautiously trying to answer back. "Hello? Sorry…can you repeat that…someone is missing?"

"You're that detective, right?" the voice at the other end managed to say, speaking coherently at last, "That one…that one he's always talking to, the one he wants to get to lock me up for being a blight upon humanity?"

"Er…" John answered intelligently, before managing, "Are you trying to call Sherlock Holmes?"

"Yes! Him, he, you! You have to help, there's all this blood, and at first I thought it was just wine, because you know, it's him, but it didn't taste right, and I can't find him anywhere and he's never awake now, and I think he's been kidnapped, and what if it's his thumbs, or his legs, or…or…you…come and…detect!"

"Sorry," John managed to say before the hysterical diatribe could continue on, "You're saying someone is missing and there's blood and…thumbs?"

"No thumbs! I don't know," the voice at the other end screamed back, "Could there be thumbs? What if the whats-its ate them?"

"Right," John said, in his best soldier voice that quieted the other speaker immediately, "Who is this, where are you, and who, exactly, is missing."

"Manny Bianco, Black Books, Bernard Black," the voice barked back obediently; John could almost hear him standing at attention through the phone. John frowned; something about those names sounded familiar. Suddenly, the mobile was plucked right out of his hands.

"Tell me everything." Sherlock took the case.