Sherlock stood, staring at the paper until Mrs Hudson brought him back to reality. "Oh Sherlock. What are you going to do?"

"Hm?" he looked up and saw the landlady's frightened face. "I'm going to find him Mrs Hudson that's what." He managed a weak smile to try and reassure her. "Now why don't you give me some space so I can work?" he asked. He needed to think. He had no idea how he was going to help John but he couldn't let her see that. Mrs Hudson nodded and left Sherlock alone.

When she was gone he rushed over to his desk and grabbed his magnifying glass he needed to find something, anything to help him. Everything on the paper was printed and that didn't help. You could tell things from people's handwriting but not from a computer printed document. Of course he would analyse the ink but he suspected it would be a mass produced type that he'd never be able to trace. He examined the photo. The room looked like it was in an old industrial building but there were hundreds of them in and around London. He would ask his homeless network to keep a lookout though, you never know he might get lucky.

His mind was whirling through all the possibilities when his phone rang. He grabbed at it hoping it would be the kidnapper, hoping it would give him some clue to help find John but it was Lestrade. "What do you want?" he snapped.

"Good morning to you too, Sherlock." Lestrade laughed "I was just calling to see if John had made it home yet."

"No he hasn't and he won't if you keep me talking. I need to find him."

"What? Why do you need to find him? What's going on Sherlock?"

"John has been kidnapped. I have a note."

"OK I'm on my way."

"Don't bother I won't be here."

"Sherlock if you know something you need to tell me. Don't go after him on your own. I can help."

"No, I mean I won't be at Baker Street. Meet me at Barts if you really want to help."

"Of course I want to help." Lestrade told him firmly and the phone went dead.

Sherlock sighed. He really hoped John was safe but right now there was nothing he could do but work on the note, it was all he had.

John was dozing in the chair when the man returned. Immediately he heard the door open he was awake and alert, watching for his chance to make a move if it should come. "Morning Dr Watson or maybe I should call you John. Dr Watson seems so formal and you are going to be here for some time." He was wearing the same mask as yesterday John noticed. He walked across the room and started to set up a video camera on a tripod. John watched intently wondering what his plan was but it would soon become all too clear.

Sherlock was starting to analyse the ink from the note when Lestrade arrived. "So what's going on?" Lestrade asked. Sherlock just handed the note over and carried on with what he was doing. "Oh God Sherlock. Have you got any ideas who this might be?"

"None yet."

"So what do you know?"

Sherlock dropped his head. He hated to say it but he knew nothing. The one time he needed to be able to solve a case quickly and he had no idea where to start. He looked at Lestrade. "John left Baker Street about 11 am yesterday and I haven't heard from him since. The note was delivered by hand about 8.30 am this morning. The paper is common printer paper used by thousands of people. I'm analysing the ink but I suspect that will be the same. The room John is kept in is an old industrial building like hundreds all across London. My homeless network are out looking but it could take weeks with nothing else to go on."

He dropped his head again. Lestrade could see the worry and frustration on his face. "OK so I'll get my team to get a warrant and access the CCTV footage around Baker Street at the time John left and the time the note arrived, see if we can find anything." Lestrade took out his phone.

"No don't." Sherlock told him. He couldn't believe he hadn't done this sooner.

"What? Why not? Surely it couldn't hurt?"

"I can get the information quicker."

Sherlock picked up his phone and dialled a number. "Hello brother dear" the voice on the other end crooned.

"Mycroft I need your help. John has been kidnapped and I need some CCTV footage."

This time Mycroft's voice was totally business like when he spoke. "What do you need Sherlock."

Sherlock explained to his brother that he needed CCTV footage from around Baker Street at the time of John's disappearance and the time the note was delivered.

"Of course. I'll have it brought to Baker Street immediately."

"No, I'm at Barts."

"Alright then, Barts." And with that Mycroft was gone.

Sherlock gave a small smile. For all their bickering he knew that he could count on his big brother when he needed him.

Within half an hour a man in a suit had delivered a box of discs with all the CCTV footage Sherlock had requested. Sherlock had already analysed the ink on the letter to discover what he already suspected, the ink was common place and untraceable so he and Lestrade got to work.

They started with the 11 am footage from yesterday and soon found John walking down Baker Street. They followed him as he passed a white van and then disappeared. Within seconds the van drove away. Lestrade looked at Sherlock "Can you read the registration?" Sherlock rewound the footage and froze it on the van. Lestrade picked up his phone and dialled. "Donovan I want you to trace a white Ford van registration DX54 VWN." For a moment there was silence and then Sherlock heard him say "Never mind why just do it." As he finished the call he looked at Sherlock "It shouldn't take long and then at least we have somewhere to start."

They then turned their attention to 8.30 am and saw a man in a black hoodie approach 221B. He was average height and of a stocky build but it was impossible to see his face with his hood up. He had a carrier bag in his hand. They watched him walk down Baker Street and into the tube station. Lestrade rummaged in the box of discs until he found one labelled tube station footage. "Your brother thought of everything didn't he?" he said to Sherlock as he handed him the disc.

They found the man on the next disc and followed him as he entered the toilets but never came back out. Lestrade sat looking confused for a moment until Sherlock muttered "The bag. Of course. He had a change of clothes. He knew I'd watch the CCTV footage." He banged his fists on the table in frustration.

"We'll find him Sherlock." Lestrade told him placing a hand on his arm trying to comfort him a little. He'd barely finished the sentence when Sherlock's phone rang.

Lestrade watched as Sherlock grabbed for it. "John?!" he exclaimed.