Disclaimer: I do not own anything to do with Harry Potter, Sherlock Holmes or the BBC series Sherlock.

Prologue

If Sherlock hadn't seen it with his own eyes, he would have believed it impossible. But his eyes and brain did perceive it and therefore it most certainly did happen; three adolescents appeared out of nowhere into the middle of a busy road in central London.

It was only chance that Sherlock saw them at all. He was in a taxi, pursuing a suspect in a murder case, when he'd become concerned that the man had escaped on foot through the pandemonium of Piccadilly Circus. He had turned to look over his shoulder through the rear window and it was at that moment that the three people materialized into existence. There were two boys (one dark haired, the other red) on either side of a girl with medium length brown hair and they were all holding hands. They were facing away from him, which was lucky for them otherwise they might not have noticed the red London bus that was about to run them over.

As they swept themselves out of the bus' path, Sherlock was able to catch a glimpse of their young faces and formal attire before they were blocked from his view.

"Where to next, guv?" asked the cabbie, bringing Sherlock back to his chase. He looked ahead and spotted the taxi his suspect was in turning down Great Windmill Street.

"Left," he instructed, casting a last pointless look up Shaftesbury Avenue to catch sight of the teenagers but the pavements were too busy.

Twenty minutes later Sherlock was frogmarching the suspect (a rather tiresome individual of minute intelligence) through the front door of Scotland Yard.

"I wanna see a lawyer," the man whined for the seventh time. "You can't do this to me – I ain't done a thing."

"Be quiet," Sherlock snapped, irritated by the man.

The sergeant on duty at the front desk raised his eyebrows in surprise at the unexpected arrival. Sherlock pushed the suspect against the edge of the desk with slightly more force than necessary. "I have a delivery for Inspector Lestrade," he explained smoothly. "Call him immediately." The sergeant opened his mouth, seemingly offended at being ordered around by a member of the public, but before the officer could protest Sherlock fixed him with a withering look. "Or if you'd prefer to take your time about it I look forward to watching you explain to your superiors why you prevented the arrest of the main suspect in the Amelia Barnes case."

The sergeant's eyes widened and he grabbed hold of the phone and started dialling at once while the man pinned to the desk exclaimed, "Main suspect! You're 'aving a laugh, mate."

"I'm afraid the state of your front left pocket and your preference for herbal cigarettes with a strong cinnamon flavour would prove otherwise, mate," Sherlock replied.

A set of double doors burst open as DI Lestrade strode into view followed closely by DS Donovan. "Finally," Sherlock muttered, before thrusting the man in the direction of the detectives, nearly causing Donovan to be knocked to the ground. "Now that that's finished I have some other business to attend to," he announced to nobody in particular and walked past Lestrade and Donovan into the inner part of the Yard.

"Sherlock, wait!" yelled Lestrade. Sherlock considered ignoring him as the Inspector was only going to say something tedious but the sound of following footsteps told him that Lestrade wasn't going to go away easily.

He stopped and turned back to the detective with an air of great impatience. "Is there a problem?" he asked.

"How many times do I have to tell you, you can't just go off on a merry chase after a criminal without police approval," Lestrade growled.

"Why not? It works," Sherlock pointed out.

"Because one of these days you're going to get in over your head and there will be no one there to save your skin." Lestrade shook his head. "You're not invincible, Sherlock."

"Thank you for your concern, Inspector. Now, if you'll excuse me." He turned on his heel and carried on to his destination. The continuation of Lestrade's footsteps made him frown. "I just handed you a murderer, Lestrade," he called, not bothering to look over his shoulder.

"You did," Lestrade agreed.

"Then why am I the one to be under your scrutiny?"

"Sherlock, you and I both know that you have absolutely no permission to be anywhere in this building." Sherlock started climbing a set of stairs and Lestrade jogged a few paces to block his way. "Where are you going?"

"I want to view some of this evening's CCTV from Piccadilly Circus," Sherlock explained truthfully.

Lestrade frowned. "Why?"

Before Sherlock could fob him off, a constable ran up looking nervous. "Sir?"

"What?" Lestrade snapped.

"Chief Inspector Chalmers wants to know why you are not overseeing the questioning of your murder suspect," the constable said and Lestrade cursed.

Sherlock walked round the irritated detective and continued his journey up the stairs. "Have a good evening, Lestrade," he said mildly as he passed.

"You've got ten minutes before I get someone to pull you out," Lestrade called up the stairs after him. "You hear me? Ten minutes."

Thirty minutes later Sherlock was still staring at the monitor in front of him, frustrated that he couldn't find video evidence to back up what his eyes had observed an hour ago. Despite Piccadilly Circus being one of the busiest junctions in London, none of the CCTV cameras were trained on where the three young people had appeared out of thin air. He was able to find and follow them along Shaftesbury Avenue but there wasn't any sign of them before that either.

He watched again as the female led the way through the bustling crowd. All three of them seemed pretty unremarkable though it was likely that they had come from a formal event given their attire. The clothing of the males had a distinctly old-fashioned look that brought to mind a wedding. They moved quickly through the crowd, throwing anxious looks at each other before they turned down an alleyway and he lost sight of them.

He left New Scotland Yard shortly afterwards and headed back to Piccadilly Circus. All the tourist shops and restaurants were closed by now though there was still enough traffic to stop him from investigating the spot where the three of them had materialized. Through the windows of the darkened shops he could make out in-store security cameras and he resolved to return there first thing in the morning.

The staffs of the shops were only too happy to show him their footage once he'd waved the warrant card he'd pinched off of Lestrade the previous evening.

Annoyingly, the cameras seemed to be solely trained on what was happening on the inside of the stores. There was very little footage of anything outside and all that he could see past the windows was of the crowds walking past.

He was not going to get the proof he needed that three people had emerged out of nothing but he knew it had happened. He had seen it. The important question now was how had it happened? As far as he was aware there hadn't been a scientific breakthrough that allowed teleporting from one place to another. He almost texted his brother Mycroft just to check but then he remembered that he hated getting in contact with Mycroft.

Perhaps it had been a conjuring trick. It was easy to use mirrors to make something instantly appear – though it was a poorly publicised illusion if he was the only one to have noticed.

He closed his eyes and focused his mind on what he had seen the previous evening. The three adolescents appeared and walked quickly to the side. The momentum they moved with suggested that they had been moving in that direction before their dramatic arrival.

He imagined that most people would have some sort of mental break down if they were to suddenly find themselves in a completely different place. But not these three. They were aware of what had happened and had most probably instigated it themselves.

And Sherlock had absolutely no idea how they did it.

A/N Thank you for not giving up and getting this far!

You probably can't watch Piccadilly Circus CCTV footage at Scotland Yard but I wasn't sure where you would go so, sorry about that.

Anyway, please let me know what you think!

Lots of love,

Lil Drop of Magic