A/N: Thanks go to musardine for French translations and elainasaunt for the beta work.

"Oi! Leave off!" Marcia looked sharply around her, but she couldn't see who exactly it was that had shoved her almost off balance as she pushed through a throng of other pedestrians. She expelled an aggravated sigh and kept moving. She was done with her shift at the Club Electra, it was late, and now she very much wanted to go home and put her feet up. The tube station wasn't very far, she could almost make out the sign.

She fumbled for her Oyster card, tucked away safe against dips in the front pocket of her jeans, but another set of fingers had beaten her to it. "Damn it!" Marcia muttered. There was a constable up ahead, but he was involved in sorting out a traffic dispute and he probably wouldn't do more than take down her details and tell her to file a report at the station. As if she had the time. It must have happened when she was shoved. Angling through the foot traffic, Marcia found a safe haven against a shuttered doorway and opened her handbag. The loss of the Oyster card was an inconvenience but it wasn't a huge loss, there wasn't more than another ride or two left on it. But if they'd taken her purse with her wages too …

An arm went around her shoulders. Marcia looked up, but she couldn't see anyone. In fact, she couldn't see anything at all but a hard, unrelenting blackness that surrounded her utterly, as if the street around her had ceased to exist and all that was left was a profound nothingness. She tried to scream but an invisible hand clamped down hard over her mouth and nose as she was lifted off her feet. Frantically, she looked around her, but everyone else had their heads down, too preoccupied to see anything, just as she had been only moments before.

Terrified, Marcia fought back. She dug the point of her elbow into what should have been her attacker's diaphragm, and followed up by kicking hard, hoping to strike a knee or even better, his groin, but all Marcia hit was air. Her lungs were bursting, exhausted from the strain of fighting without any fresh intake of oxygen. She was going to die, right there on the pavement, and no one gave a flying monkey's. As her senses faded, Marcia looked up and saw the parody of a man's shadow looming out of the blackness. It laughed at her, and the sound echoed weirdly against the roaring in her ears as she lost consciousness.

Paul McDaniel woke up screaming. He snapped on the lamp and looked around his study with haunted eyes.

The room was quiet. The street outside his window was quiet. Still a crawling sensation climbed his spine and made the undersides of his arms damp with sweat. He had the distinct impression that he wasn't alone. He looked up and his eyes widened. The shadow of a man, his shadow, carried a body in its arms.

He looked down into his lap and found the small, brass nameplate, etched with the name 'Marcia'.

It hadn't been a dream.

John looked at the man sitting before them and felt an immediate sense of concern. He wore baggy clothes over a shrunken frame. It was clear he'd had a recent and sudden weight loss. His complexion was lacklustre and his cheeks hollow, as if he'd had been recently ill, and made it made his beak-like nose more prominent than it must have normally been. There was an accumulation of lines around his eyes that seemed at odds with his relative youth. His hair was coming in grey at the roots, but was otherwise a rich, chestnut shade of brown. Even the slumped bow of his shoulders suggested that he was feeling a great deal of strain.

But it was his eyes, his gritty and bloodshot eyes, that really expressed how terrified their caller was. He'd said he was afraid to sleep, lest the worst happen, and that fear showed in his eyes. On its face, Paul McDaniel's claim seemed impossible, yet Sherlock was leaning forward with an expression of keen interest.

"And you say this prisoner, Bouchard, has a reputation as some sort of voodoo priest?" Sherlock asked.

"Some say voodoo, some say he's made a pact with the Devil. There are lots of stories, Mr Holmes," McDaniel replied, "and it's impossible to say which ones are fact and which are fiction. What's for certain is the other men are terrified of him. There's something about him." McDaniel pressed his lips together until they flattened into a thin line, and then he shook his head as if he was frustrated with his inability to explain himself.

"He's not a large man. In fact, if you saw him from across the prison yard, you'd take him as one the guards would need to look after to keep – "

McDaniel looked away for a moment. "Well, you know the sort of thing that can go on. But no man would dare. It's said that a prisoner tried, not long after Bouchard's arrival, and he was never quite the same after. In fact, he was transferred out, sectioned for his own protection."

He drew a shaky breath and let it out again. "I've seen bad people since I've worked in the prison system. A few that I would call genuinely evil. But when I'm around Bouchard, I feel a sense of cold dread. He's malevolent, Mr Holmes, and now he's cursed me."

"But why?" John asked. "Why would he target you?"

"It was my report to the parole board, I expect." McDaniel shrugged helplessly. "What else could I do? He'd been involved or implicated in multiple incidents that demonstrated he was still a threat. I had no choice!" he said vehemently. "But Bouchard doesn't like it when he doesn't get his own way. He had tired of the petty fiefdom he'd created within the prison and felt it was time to move on. Based on my report, the parole board disagreed."

"He threatened you specifically?" Sherlock asked. "How?"

McDaniel shook his head. "He said he would get even with us all, but he singled me out to make an example. He said once he'd brought me down, the others might learn and change their minds."

"Yes, yes," Sherlock said impatiently. "But what exactly did he do?"

"He cursed me, Mr Holmes," McDaniel said as he twisted his hands, clearly uncomfortable with what he was saying. "He's made me afraid of my own shadow. At first it was little things, but then … " McDaniel swallowed visibly and untangled his fingers. He hesitated, and then reached into his coat pocket. He withdrew a small parcel and handed it over. "Don't touch what's inside."

John gave McDaniel a reassuring smile. "I'll get some gloves."

Sherlock had been using the dining table as a lab bench and it was arrayed with an assortment of test tubes and dissection instruments. There was a box of latex gloves holding a notebook open. John glanced down at the the carefully drawn depiction of broken muscle fibres and marvelled at the exacting detail. It was an illustration for Sherlock's latest monograph on ceramic knives and stab wounds. It was an ugly subject, but he couldn't help but appreciate the beauty in Sherlock's work.

John collected the gloves and handed them to Sherlock. He put them on without comment and then carefully opened the small paper bag and took out the contents. Inside were three name tags.

"I swear to you, Mr Holmes, on my parents' graves, I had nothing to do with these deaths. At least not willingly. And yet – " McDaniel pointed helplessly at the incriminating evidence. "How else could I have obtained those?"

"There were only two murders reported in the paper," John said.

"And now there are three," Sherlock said as he examined the small brass badge belonging to a local casino.

"I'm going to turn myself into the police," McDaniel said. "But even if I'm locked up, it won't do any good. Bouchard will just turn his campaign of terror on some other hapless person. Help me end this, please."

Sherlock put the name tag back onto the bag and set it aside. He picked up his coffee and sat back in his chair. It was obvious he was thinking. "Your sense of honour does you credit, Mr McDaniel," he said after several moments, "but let's leave you out of the police's line of enquiry for now. Go home."

"Sherlock!" John said, his surprise obvious. "Sherlock, a word?" He jerked his head towards the kitchen.

"Will you excuse me for a minute, Mr McDaniel?" Sherlock said politely. "My colleague wishes to tell me, in private, that I'm being too trusting."

John felt his cheeks redden, but he shrugged at their guest as he got up for a second time and followed Sherlock into the kitchen.

"Well?" Sherlock said as he leaned against the counter and crossed his arms. He looked down on John with tolerant expectations.

"It's fantastic!" John said as soon as he'd shut the divider to the living room.

"And yet his story would be easy enough to corroborate," Sherlock replied. "He lives on the seventh floor in a secure building. CCTV and a 24/7 doorman."

"What are you thinking?" John asked.

"That McDaniel is an innocent man," Sherlock replied. "Or at least as innocent as he can be under the circumstances. What do you make of him, John?"

John studied the floor as he collected his thoughts and then he looked up to meet his companion's eyes. "I'm not a headshrinker, Sherlock, but it sounds to me like he's had some sort of mental breakdown. You saw the state he's in, a campaign of intimidation could do that. He's cracked under the strain of it, and he needs help himself."

"Then we shall give it to him, John," Sherlock said. "Come on, I want a word with Lestrade. If it makes you feel better, you can go with McDaniel. See him safely home and talk to the doorman. Get the CCTV if you can. I'll arrange for some additional surveillance so you can meet me at the crime scene."

"What crime scene?" John asked.

Sherlock gave John a look that said he should know better than to ask questions when the answers were obvious. "The police only know of two victims. We know there's a third." He smiled encouragingly. "Come on, John, this case is getting more interesting by the minute!"

John pulled his jacket tighter against his body as he stepped out onto the street. There was a cold wind blowing, and he was already chilled. He'd seen the layout of McDaniel's building; a modern high rise with state of the art security systems that would be nearly impossible to beat. The head of security had given the tour himself, and he and his team were keen. No one got in or out without their knowing about it.

When John explained that he was a doctor, and it was possible that McDaniel had developed a sleep disorder that caused him to roam at night, the security chief had been sympathetic and shown John to the suite where they stored the video records. They'd checked them all and confirmed that McDaniel hadn't left his flat on the nights in question. Moreover, he'd offered to keep a special eye out, just in case McDaniel did show signs of roaming.

It was no comfort to their client. Paul McDaniel had just turned those haunted eyes on John and asked, "Now do you believe me?"

Someone was playing a bright tune on a guitar. John looked up, distracted from his worried musings, and spotted the busker. The young man tipped his hat, smiled, and broke into All Along the Watchtower. John nodded back at Sherlock's promised sentinel, and as he paused to listen he dropped twenty pounds into the guitar case. "Cheers, mate," the busker replied. "Tell Mr Holmes I'll keep a sharp eye."

"That's appreciated," John said. "Call in straight away if you notice anything at all. This is a weird one."

The busker nodded again as John's phone rang.

Lestrade looked up at a smiling Sherlock Holmes and got a rotten feeling at the pit of his stomach. That Sherlock had decided to get involved in this particular case could only mean one thing, and that was matters were going to get much worse than they already seemed, and they were going to do so sharpish.

"Inspector!" Sherlock greeted him cheerfully.

The rotten feeling intensified. There was no point in doing anything but cutting straight to the chase. "What have you heard, Sherlock?"

Sherlock shrugged back as he glanced casually around the incident room. "Only that there's going to be another dead body on your patch."

As announcements went, it was fairly mundane. The killings had all the hallmarks of a serial, the only question was how long was it going to be before the latest lunatic in their midst struck again. Still, they'd been closemouthed about what information had been released to the press, so Sherlock must have noticed something about the cases from the statements that had been made.

"Ta for that," Lestrade replied. "Any idea what's going on?"

Sherlock continued to scan the room, his attention only partially on the conversation. Then again, Lestrade thought to himself, maybe Sherlock's consulting room had been quiet and he'd got bored. This could be a fishing expedition.

"Gov!" Lestrade looked away from his guest at the sound of his name being called. Perkins, an officer only recently transferred to CID, looked grim as she jotted down notes on a pad and then hung up the receiver. "We've got one."

It was obvious that Sherlock was trying not to be smug, but an air of self satisfied pleasure practically radiated off him. Lestrade did his best to ignore it. Obviously, Sherlock had been tipped off, although in all likelihood, the how would remain a mystery unless he felt like bragging. "Where?" Lestrade said to Perkins.

She glanced down at her notepad and then at the map on the board as if confirming her information before she reported. Lestrade filed that observation away. Perkins was a good officer, methodical and careful, but it seemed she didn't trust herself. Lestrade didn't know if it was because she was worried about messing up in front of her new boss, or if she was generally insecure.

"Not far from the last one, sir. Uniform has secured the scene, and SOCO is on the way."

"Right," Lestrade said resolutely. "Sherlock, you ride with me."

The circus was well under way by the time they arrived on scene, and there were more than a fair few number of gawpers taking in the show. Lestrade sighed as he signed the attendance sheet and handed it over to Sherlock so that he could do the same.

Anderson walked up to meet them. He pulled his mask off and shook his head rather mournfully. "Bin man was emptying the skip." He pointed at the open bay doors of an ambulance. A big man, who looked severely shaken, clutched at a blanket with one hand as a constable pressed a cup of what Lestrade presumed to be tea onto him. "It's not very pretty."

"Forensics?" Lestrade asked as he snapped on a pair of exam gloves and approached the dump site.

"Nothing obvious. Maybe at the lab," Anderson replied.

Sherlock had his mobile out. He was snapping photos like a tourist. Lestrade felt an overwhelming urge to knock the thing out of his hand as he took several shots of the disfigured young woman next to the rubbish skip. He heaved a sigh. Such a waste of a young life. "Anything?"

Sherlock put his phone into his pocket. He was careful not to disturb the crime scene as he knelt next to the body and peered at it closely with a pocket lens. "Curious," he said softly and then rose to his feet. He looked puzzled and that didn't reassure Lestrade at all.

"Sir!"

"Yes? What is it?" Lestrade tore his gaze from the body and turned towards the constable who had called his name.

"CCTV from the street camera, sir. We might have something."

"Right!" Lestrade clapped his hands together and rubbed them in anticipation. "Let's have a look."

"That's it?" Donovan said, expressing the disappointment that was etched into all of her colleagues' faces. "All we can see is a shadow."

"It's something," Lestrade said as he leaned over the evidence technician's shoulder. "Enhance the image, don't worry about the skip or anything else." He turned his head and regarded Donovan. "It's our man. Damn it, how does he keep avoiding the cameras?"

John shot a look at Sherlock and saw he was frowning. The stay at the crime scene had been brief and had contributed little to their knowledge of the previous night's events. It would be up to forensics to tell the tale. "Sherlock," he said softly. The shadow, though grossly distorted, bore a striking resemblance to Paul McDaniel.

"Yes, John," Sherlock replied. He sounded amazed. "I see it too."

Her gentlemen callers were solemn as they entered the autopsy bay. All except for Sherlock, whose step was light, as if he hadn't a care in the world. "Molly Hooper," he said in an expansive tone, as if she was his favourite person. Maybe, just for those few moments when she had a fresh corpse on the table, she was. "Lestrade says you have news."

Molly pulled the sheet back on the young woman's body. She had been pretty once, but no one would call her that now. Not with her bulging eyes and a mouth that seemed frozen in a permanent scream. "I've never seen anything like this, gentlemen," Molly said quietly. "The cause of death is asphyxia, but there's no finger or ligature marks on the throat, and no broken hyoid bone from strangulation, just the petechia in her eyes and the discolouration of her skin." She shrugged helplessly. "It's like the others. As if she simply lost the ability to take in air."

"Any skin under the nails?" Lestrade asked. "Anything useful at all?"

Molly shook her head. "She just died, Inspector. And though it's not logical, based on blood analysis, I'd be very inclined to put down the cause of death as fright."

"It's incredible," John said. "I suppose it wouldn't be the first time a murderer has tried to set himself up with a police alibi, but there's something about this. Sherlock, I think he's telling the truth."

"Quite," Sherlock replied absently as he booted his laptop. "Sandwiches and coffee, John. I think we're in for a long night."

The computer finally came to life. Sherlock typed. And frowned. He typed some more and the frown deepened. Operating off the theory that sometimes fiction concealed the truth, he opened a few of the more promising sounding web pages and scanned their contents. Finally, just as John walked in balancing two plates of sandwiches and two mugs on a tray, he shut the machine down with a disgusted sigh. "The information superhighway, my eye," Sherlock said disgustedly. "Do you know what comes up when I query shadow magic, John?"

"Myths and legends?" John speculated. "A compendium of spells suitable for beginning witches?"

"Role play games," Sherlock said fiercely. "A complete waste of time. No, it's old school research for us." He rose, set the computer down in his chair, and went straight for his coat. The weather had been cold and clear all day and the night promised more of the same. "We're off to the library. The Bodleian might be a better choice, but under the circumstances we don't have time to go to Oxford, so the local will have to do. Come on."

"What about lunch?" John asked.

Sherlock gave John a disgruntled look. "We'll eat it for supper," he replied and swept down the staircase to hail a taxi as John hurried to catch him up.

"Ah!" Sherlock said, sounding pleased as his gaze swept around a room filled with floor to ceiling stacks of leather-bound books. "This is more like it."

"Ssh!" From a dozen carrels came an angry shushing sound from the people toiling away around them.

"Sorry!" John faux-whispered and received another round of death glares in turn.

Sherlock jerked his head sharply towards the reference desk. John rolled his eyes and followed. He was a man on a mission, and in this case the mission was to arm himself with as much knowledge as he could about something that couldn't possibly exist. It seemed hopeless.

Still, what else could they do? The police had three bodies. He and Sherlock had the name of the man who confessed he was guilty, and yet everything, except that damning bag of evidence, suggested that there was no way he could be responsible for the deaths.

What was it Sherlock liked to say? John asked himself, and then he remembered. 'Once you eliminate the impossible, whatever remains, no matter how improbable, must be true.'

There was every reason to believe in Paul McDaniel's innocence. He was a good man, dedicated to helping those who most thought were beyond hope, and he was willing to hold his hand up, even though physically there was no way he could be in two places at once. Unless Bouchard's curse was real.

The question was: even if they could prove there was such a thing as a curse that would let you steal and manipulate someone's shadow, what could they do then?

It was hopeless, John concluded some hours later. He shut the cover on one ancient tome and then glanced around the room as he pulled another one carefully towards him. The clerks assigned to assist them were covertly shooting daggers, and shadows were starting to fill the reading room, another reminder of just how much time they'd lost on their fruitless quest.

They'd divided the research between them. Sherlock had taken the volumes written in French and Italian, whilst John had taken on the German ones, a language he could read reasonably well, and speak a bit of, although he'd never take home any prizes for his accent. They'd split the works written in Greek and Latin. Many of the serious scholars on the topic of magic preferred to publish in classical languages. John was saving those texts for last. Sherlock was fluent, but John's knowledge was limited to medical terms. He could pick out key words from a list they'd devised, but not much more. From somewhere that wasn't entirely clear, they'd also acquired a pair of students who pored over volumes written in English from the days before Dr Johnson's dictionary, just in case the local alchemists had something useful to say on the subject.

Based on what they knew of Bouchard, their answer could be in any of the books before them. For a hard man from a tough council estate, he was something of a scholar, and was known to be fluent in several languages. It was his bookishness, combined with his diminutive stature, that caused other prisoners, unfamiliar with his reputation, to make him as an easy mark.

John took a breath and returned to his work. In their quest to learn more about shadow stealing he'd read all sorts of weird stories. Many of them had been about various types of possession and mystical coercion and the subsequent exorcisms and other forms of throwing off untoward influences. They were all uniformly horrific. He tried not to imagine what the poor souls were actually suffering from. To his medical mind it seemed as if in many of the cases the victims were ill with some physical or mental malady. But there were a few that gave him genuine pause, and those kept him turning dry and dusty pages looking for clues to their current dilemma.

"Got you!" Sherlock crowed. "John, come quickly. Look!"

One of the clerks heaved a noisy sigh of relief. They'd received authorisation from on high to allow Sherlock and his party to stay on after closing, and now it seemed if perhaps they might be allowed to lock up sooner rather than later.

John studied the passage Sherlock pointed at. The book was in French, and very old. He could pick out a few words, mostly from their Latin origins, but the majority of the text was lost on him. "You'll have to read it for me."

"It says, 'to capture the soul one must steal the reflection'," Sherlock translated. "This is it! I'm sure of it. Ingenious!" His gaze became faraway. "Yes, I can see how Bouchard managed, given his purported force of personality. You'd need that to carry this off. It's lucky for McDaniel I can be just as persuasive."

John frowned. "But Sherlock, this is magic. Real magic! Isn't that out of your bailiwick?"

"Bouchard is a thief," Sherlock replied sharply. "A thief of souls and lives. Who better for me to take on?"

John had nothing to refute that with. "Fine. If you're set on not confronting Bouchard directly, what do we need to do next?"

"Mr Holmes, thank God." McDaniel's eyes were rimmed with red and his lip trembled as if he might cry. "I heard about that woman. That poor woman. You've got to stop this!"

In the mortuary there were three corpses, and all of them died with identical expressions of horror contorting what had once been young and pretty faces, and yet John wanted to reassure McDaniel that this wasn't his fault. "Sherlock's working on it, Paul. You've got to give him time."

The find at the library had led to another, far more productive Internet search, one that had concluded with Sherlock having a lengthy conversation with the pre-eminent expert on Afro-Caribbean magic and folklore, a Dr Léonine Fontaine in Martinique. The conversation had occurred in French, and as night fell and the street lamps burned with an amber glow, Sherlock had become more and more animated, pacing and shooting rapid-fire questions at Dr Fontaine until the battery on the phone threatened to die. 'Merci! Merci beaucoup!' Sherlock said before he disconnected. When he turned to face John he was smiling like a hunter closing on his kill.

"Do you recall Peter Pan, John?"

John goggled at Sherlock. Of all the things he'd expected to hear after such an animated and incomprehensible conversation, the last was mention of a beloved children's classic. "Yeah?" he replied uncertainly.

"In it," Sherlock explained, "Peter seeks out Wendy because his shadow has come loose, and he wants to have it reattached once more. Peter can't sew, but Wendy can!"

"Uh huh?" John replied uncertainly.

Sherlock clasped John around the shoulders. "Don't you get it?" he asked with a growing expression of frustration. "Bouchard has used magic to tear McDaniel's shadow asunder from his body and then coerced it to do his bidding. We have to wrest it free again, and then reattach it to McDaniel!"

"You do realise how mad that sounds?" John asked. He shook his head, pinching the bridge of his nose against an oncoming headache. "And even if we can, what do we tell the police? That Bouchard killed those girls by remote control? They'll never buy it, and even if they did, how could they prosecute?"

Sherlock waved his hand dismissively at John. "We'll deal with Bouchard later. Right now, we need to reunite McDaniel and his shadow."

Which is why they were in McDaniel's flat and John was holding a bag which contained, amongst other things, a candle, a piece of rope, and a large hat pin, and Sherlock was stalking around the combination living room and study, examining each item of furniture and decoration with the greatest of interest.

"This is essential, McDaniel," Sherlock said harshly. "This mirror: is it new?" He strode over to a piece of etched glass in an intricately carved ebony frame.

McDaniel shook his head. "I've had the mirror for ages." His face brightened as Sherlock's fell. "The frame is new, though. Some of the prisoners I've helped made it for me as a birthday gift."

"A birthday!" Sherlock took a magnifier from his pocket and examined the frame closely. "Ingenious." He pocketed the lens again and strode around the room once more. "Yes! I can see it now!" he said as if all the pieces had slotted neatly into place.

"I'm glad that's one of us," John said softly. "Sherlock, are you sure about this?" he asked as he passed over the hat pin, and Sherlock carefully tucked it into his shirt cuff. He understood the mechanics, or at least he thought he did, of the spell Bouchard had allegedly used, but to actually see the set up was disconcerting. "Bouchard used that mirror to hex McDaniel's shadow and bend it to his will?"

Sherlock nodded. "Somewhere, secreted in his cell," he said softly, "Bouchard has another mirror decorated with these same markings. Probably not as large. But from his end, it wouldn't need to be. All he'd need is something big enough to use as a focus. That, and a candle." He turned away from John, staring into the middle distance as he often did when he was thinking.

The was a movement in the corner of his eye. John clocked it and turned. His jaw dropped. "Sherlock!" he whispered harshly. Sherlock ignored him. On the wall, McDaniel's shadow, independent of any light source in the room, began to grow. "Sherlock, damn it, climb down from your turret and look!" John jerked Sherlock roughly by the shoulder and pointed.

McDaniel paled and threw a hand against his mouth and then collapsed to the floor overcome by shock.

"Shit! What do we do?" John said. He pulled his Sig and aimed it, but what use was a bullet against a shadow?

Sherlock stared as well, although his expression was one of fascination. He shook his head and used his palm to redirect John's line of fire to the floor. "Get McDaniel!" he ordered. "Hurry! We haven't a second to lose!"

Lestrade shivered in the cold. He and his team and every officer they could sweet talk was out, keeping a watchful eye on Leicester Square. Sherlock had gone missing. That was worrying, but then he had his methods, and most of the time they didn't coincide with police procedure, so it was probably just as well he was playing Lone Ranger. What Lestrade didn't know about what Sherlock got up to wouldn't hurt him, and it might just save his career.

He scanned the throng, looking for potential targets. The perp didn't really have a type other than young working women. Two of their victims had been croupiers. One had been a waitress. One potential lead had been of interest: all three had name badges as part of their uniforms, and yet there hadn't been any badges among the women's belongings, either at the clubs where they worked or on their bodies. It was possible that the killer had targeted them just so he'd have something with the women's names on it as souvenirs.

They'd used that tiny clue to plan their stakeout, placing officers close to the clubs and casinos, and advising the management to see their female employees were escorted to taxis or the tube station, not that many of them would listen.

A gaggle of attractive young women left the club two doors down from his vantage point. Three of the girls got immediately into a taxi, but their companion, a sturdy twenty-something with a spill of long auburn hair who looked like she probably had spent the night serving drinks, shook her head and turned towards the tube station.

Lestrade fell in a discreet distance behind her. He had a feeling in his gut as soon as he saw the young woman, and as he'd learned long ago, that was a feeling not to ignore.

They walked briskly, threading their way through the rest of the weekend crowd. She was smart, Lestrade noted, and seemed well aware of those around her, unlike many of the other pedestrians who were stuck in insulated bubbles of their own making.

They weren't far from the tube station. Maybe he'd been wrong. Lestrade ducked and wove around a guy who was only paying attention to his iPlayer, and then looked for the waitress. His gut twisted nervously. She'd just been in front of him, and now …

He broke into a trot, pushing through the crowd. "Damn it!" he said softly as he searched. "Where has she gone?"

The woman with the long auburn hair had vanished.

Over their heads, the shadow loomed menacingly as Sherlock began to recite the incantation in French. John drew a breath and let it out slowly again as the first surge of adrenaline hit his bloodstream. "Right," he muttered, unwilling to do anything to distract Sherlock.

Sherlock had explained the ritual. Flame to draw the shadow. The rope to make a circle and contain the energy invoked by the incantation, and the pin to rejoin what Bouchard had unnaturally separated.

First the rope. John stretched the rope over his head, showing it to the shadow, and then he dropped to his knees and formed the length of white cotton into a semi-circle on the floor. He half carried, half dragged McDaniel inside and then set the candle next to him. McDaniel nodded at John shakily and then closed himself up inside the circle. Finally, he lit a match and touched it to the wick.

"De la lumière à l'obscurité. De l'obscurité à la lumière. À ce cercle j'astreins l'ombre errante."

'Light to shadow. Shadow to light. To this circle I command the wandering shade.'

Over and over Sherlock repeated the incantation in French as John and McDaniel recited the same words in English.

On the wall, the shadow jerked and shifted as if some invisible hand yanked it by its shoulder. It seem to fight the summons, and as it turned on the wall, there was something in its arms.

John stared, transfixed and horrified. In the shadow's arms as it turned towards them was the form of a woman, her long hair cascading down from her head. She was struggling. They were too late. Bouchard's experience was going to win out against Sherlock's determination to see justice done.

The candle flickered. Its flame ebbed dangerously as if it might go out.

John pulled his gaze away from the oncoming catastrophe on the wall as he realised there was no place for doubt. He must believe in Sherlock. Magic was driven by faith in the ritual; without faith it was nothing more than empty words and futile gestures.

Sherlock's voice boomed against the walls of the flat. John closed his eyes and repeated the incantation. "De la lumière à l'obscurité. De l'obscurité à la lumière. À ce cercle j'astreins l'ombre errante."

The candle's flame strengthened.

Tammy struggled against an invisible foe, kicking and throwing her head backwards, hoping desperately to connect with something.

She couldn't understand. One second she'd been on a brightly lit street, surrounded by people and noise, and the next ... there was nothing, utterly nothing, just strong but invisible arms holding her tight and cutting off her air by pinching shut her nostrils and clasping a hand over her mouth.

She was going to die. Just like the other girls who had gone missing only to have their bodies dumped in dirty alleyways like yesterday's rubbish.

She didn't want to die. Mark had just asked her to go to the pictures on their next day off, and she'd been hoping he'd ask for ages. She wanted to live. She wanted to go home and play stupid games with her budgie, and giggle over cute actors with her mates. It wasn't much of a life, but it was hers, and Tammy was going to fight for it with her dying breath.

The candle's flame, once a fragile thing, burned bright as a signal flare. The shadow on the wall could no longer resist the summons. It came off the wall and crept towards McDaniel in his circle of rope.

"De la lumière à l'obscurité. De l'obscurité à la lumière. À ce cercle j'astreins l'ombre errante."

The shadow of the woman became insubstantial and disappeared. John wasn't sure what that meant, but he hoped for the best.

Lestrade was desperate. He flagged down a uniformed constable and gave her a sketchy description of the woman he'd been following before she disappeared. The PC nodded sharply. "I'll fall back." She glanced up and down the street, assessing possibilities. "Maybe you got ahead of her in the crowd. My partner's up in front of us. Between the three of us, we'll find her, sir."

It was a knock to his pride, but under the circumstances, it made a hell of a lot more sense then the woman disappearing into thin air. Lestrade nodded. "Get moving, Hammond," he said, but she was already jogging away.

Lestrade closed his eyes and recreated the moment when he'd last seen the woman with the long auburn hair. She'd been under a street lamp, just a few yards back and close to the mouth of an alleyway. "Shit!" He'd looked away when he dodged the kid with the iPlayer. In that space of seconds, someone could have grabbed the woman and yanked her into the shadows. He ran after Hammond and towards the mouth of the alleyway. As he closed he heard a gasping cry for help.

For a heart pounding moment, McDaniel's shadow teetered on the edge, as if it wanted to cross the threshold but didn't quite have the momentum required. McDaniel opened his eyes and reached out, and insubstantial black fingers stretched forward to touch solid flesh.

"Now, Sherlock!" John cried.

Sherlock leapt into action. He pulled the hat pin from his sleeve and raised it high above his head, repeated the incantation one last time, and stabbed McDaniel's hand where it brushed against that of his shadow.

McDaniel cried out in surprise and pain — they'd neglected to mention the ritual required Sherlock to bind the shadow with blood — and he clutched his hand to his chest. "It's done? Isn't it?" he asked tremulously.

"Not quite," Sherlock replied harshly as he snatched up the candle and the rope, breaking the circle and releasing the energy within.

"Follow the path and extinguish the wielder of the flame!" he commanded. Using the rope like a lash, he struck the centre of the mirror with the intricately carved frame and then pulled the others behind an overturned occasional table and raised his coat like a shield to protect them all as a shock-wave of energy blew the mirror to shards.

"Help me! Somebody help me, please!" Tammy cried weakly as she gasped air into her starved lungs.

The pounding of approaching footsteps gave her a tiny boost of strength and she used it to pull herself up from the dirty tarmac until she wobbled on her knees. "Please!" she gasped again as a man with silver hair and worried eyes, and a female constable, peered into the mouth of the alleyway.

"Gov!" the PC said.

"I see her!" The man gave Tammy a kind smile. "It's okay, love. I'm a police officer. You're safe now." He turned to the PC. "Get an ambulance."

Tammy nodded at her rescuers and then burst into tears.

Bouchard frowned and redoubled his efforts. McDaniel's shadow, usually so easy to bend to his will, was fighting him. It was almost as if someone with a superior force of mind was lending his strength to that of the troublesome prison therapist's. He stared into the shaving mirror with the carved ebony frame and visualised the scene on the faraway street with utter clarity. But rather than the perfect vision of McDaniel's shadow holding a helpless girl in its arms, light filled the glass. Bright, burning light. Bouchard broke off the chant and threw up a hand to guard his eyes. Intense heat seared his flesh and he screamed as he died.

"What just happened?" John asked. "Sherlock, what did you do?"

Sherlock straightened and brushed bits of glass off of his coat. "Basic physics, John; energy can be neither created nor destroyed. I summoned the energy to cast the spell and then once I was finished, I sent it back on Bouchard." He turned to McDaniel. "I believe you'll find when you return to work that there's been an incident at the prison. There'll be no more problems with Philip Bouchard."

"Do you mean he's …" John trailed off, unwilling to say the words.

Sherlock shrugged at him, as if already bored by the discussion. "Rough justice, perhaps, but no more than he deserved."

"There was the shadow of a woman on the wall. Do you suppose?" McDaniel said hesitantly.

"She was fighting," John said. "I think we were in time." He frowned at the blood dripping from McDaniel's palm. "Here, let me see to that." He pulled the last item, a small first aid kit, from their paper sack of supplies, and led McDaniel to the kitchen to bind the wound and put the kettle on.

It was much later. John sat in his armchair with his computer in his lap, the lid open and the cursor blinking on an empty word processor page.

Sherlock entered from the kitchen with a tray in his hands. On it was a brandy bottle and two glasses. He set the tray down on the table and then went to John and shut the lid on the computer. "I think this is one for the dispatch box," he said softly.

John looked up, and after a moment he nodded. "Yeah. I think you're right. Who'd believe that a convict was using a kidnapped shadow to commit murders in Leicester Square?"

"No doubt your readers would be fascinated," Sherlock said. "But I'd prefer it if my reputation, at least for the foreseeable future, was based on my skills as a scientist and a detective rather than any minor talents I may have as a sorcerer. After all, I need to keep a few tricks up my sleeve."

John shook his head and smiled softly. "You astonish me, Sherlock. Just when I think I've learned all there is to know about you, there's something else."

Sherlock poured two generous measures and handed one over to John. "To the successful resolution of a most interesting case."

"Sherlock, what about the police?" John asked as he contemplated the tawny liquid in his glass.

Sherlock frowned. "What about them? The killings will stop. Granted, the murders will remain open and as far as they're concerned, unsolved, but practically speaking, that's a matter of accounting. Lestrade will probably pull the files out from time to time to see what it was he missed, but eventually the murders will fade under the weight of more pressing investigations."

"Yeah, I suppose you're right," John replied.

They drank in silence, and under the influence of the brandy's warmth, John began to put the events of the day into their proper perspective. It had been an exciting and unusual adventure. Lives had been saved and villains defeated. Once again he and Sherlock had proved themselves up for a task that was beyond the abilities of the police, and for now, how they'd managed would remain their secret.