Author's Note: First, thank you for the kind comments on my first story. This is chapter 5 of 7 - so only two more to come. Chapter 6 and 7 are already finished but need a bit more proofing from my wonderful Beta Jack63Kids. So don't worry, I'm not going to suffer from Writer's block and leave you - and poor Greg - hanging. :-)

Not sure if I have to mention that I obviously don't own any of the characters. ACD, Steven Moffat and Mark Gatiss are the rightfully entitled writers.

5

It was close to 2.30 in the morning when John woke up with a strong sense of being watched. A shard of light fell in the room. It illuminated the outline of Sherlock, who was sitting with his knees drawn to his chest at the foot of John's bed, looking at his friend calmly.

John blinked, not believing this was happening. Maybe if he ignored him. He turned onto his other side and closed his eyes again. It didn't help. John still felt his friend's eyes boring through him.

After a minute or two he felt Sherlock shifting. He thought for a moment he had actually won, that the detective was leaving. Instead the duvet was lifted and a pair of rather cold feet took residence against John's calves.

The doctor gasped, and gave up. Quietly, for he didn't want to disturb Mary, he slipped out of his bed, and padded out of the room. Only a gentle rustle of the sheets betrayed Sherlock following him.

John walked down into the living room. He sat down on one end of the sofa, pulled his feet up and slipped them under a folded blanket. Sherlock quietly sat down on the other end of the sofa, mirroring the doctor's position and wiggling his rather cold toes under the blanket to warm them.

"You're going to get socks for Christmas this year," John told him. "What is so frickin' important, Sherlock, for you to wake me up in the middle of the night?" John held up his hand, before Sherlock could answer. "It can't be that important, otherwise you would have chosen a less subtle method of waking me."

"It's 2.40 now, well beyond midnight, the test results won't be available for another hour..."

"Please, don't tell me you were bored," John grumbled.

"No, I'm not bored. In fact I have a question that needs an answer which I can't provide myself."

John blinked, shook his head in surprise and got up. He walked into the kitchen, rummaged around in a drawer, uttering an "ah, there". Sherlock heard a click, swish and click before the drawer was closed, and John came back.

"What was that about?" Sherlock asked curiously.

"I got a red marker and marked this legendary day in the calendar. The day Sherlock Holmes didn't have an answer to a question."

Sherlock pouted but, knowing his friend would leave eventually, he asked, "Why was Miss Coons talking to her dog?"

John looked nonplussed. "Why what?"

"The dog handler. When we were leaving I saw her talking to her dog. Dobby. What sort of name is that anyway?"

"Dobby is a house-elf," John answered absent-mindedly. He heard Sherlock inhale, and held up his hand.

"A house-elf from the Harry Potter books. Fiction."

"Ah!" Sherlock had heard about those books, knowing that John had read them with great interest.

"So, why was she talking to her dog?" Sherlock asked again.

"There are several reasons why she could have talked to her dog," John said, scratching his left eyebrow. "Dogs, pets in general, don't betray your confidence, they listen, they don't criticise, they don't laugh at you, they know when you're not feeling well, comforting without ulterior motives." John produced a snorting sound. "Those are the reasons I can come up with off the cuff."

Sherlock nodded, more or less understanding the concept. "Dogs don't mark dates in a calendar," he added.

A smile crept on John's face.

"Can I go back to bed now?"

Something beeped, and Sherlock walked to the lab in a hurry. "I guess not," John mumbled, pulling up his pyjama bottoms, and following Sherlock.

The detective bustled around the small room, comparing notes he had made with a diagram on the internet.

"The soil I've discovered in the carpet clearly comes from the Thames embankment. The question is from where. The other particles are from a weed that has been cultured in a laboratory. It's a cross-breed between chickweed and bindweed. Both weeds grow really fast, produce plenty of triclosan and are used to detoxify contaminated areas. Usually former industrial areas where the buildings were all or mostly torn down."

John laid out a large map of London and Sherlock pointed to three areas near the Thames where those weeds were currently used. Two sites in London's east, the other one in the west.

"Former chemical plant here," Sherlock pointed at the area in the west.

"Ex-military shipyard here." Sherlock pointed to one area in the east.

"And that area," he pointed to the one in London's very east, "has such a fat 'CLASSIFIED' printed all over it I couldn't find a single bit of information."

"Mycroft could," John suggested. Sherlock looked like he had suggested tearing out his fingernails.

John scratched his chin. "What about that piece of foil? Anything special about it?"

"Not much, the letter H is visible but with just this, a product name is difficult to deduce. It's most likely blister-foil. Sherlock got up. Let's go, we start with the classified area."

John hurried up the stairs, quietly grabbing his clothes. He wrote a note for Mary and got dressed. When he came down Sherlock was ready to go.

"By the way, those nicotine-patches suck," Sherlock told John, who had difficulties hiding his grin.

They went outside.

"Mary will need the car in a few hours. Let's grab a cab," John said, waving one over.

"Any objections if I ask Stacy and Dobby to join us? We might need a sniffer dog."

Sherlock shook his head. "Might be useful. But only if she's coming without other forces. We can't have half of the Metropolitan police trample around."

Stacy answered after the second ring, sounding only a little tired. Yes, she would join them, but she had to bring along another dog. That was acceptable to Sherlock, so John gave her the address and hung up.

They sat in the cab in comfortable silence, looking out into the night. Twenty minutes later the cab pulled over, and they got out.

They had just left the cab and were walking towards the Thames when John heard a rather well-known piece of music from the movie Psycho. John's eyes were bulging when Sherlock pulled out his phone.

Sherlock's face indicated that his brother Mycroft was calling, before the detective took the call.

He listened for two minutes, and hung up without further ado.

"Since when do you have Psycho for a ring-tone?"

"Two weeks. Only for my brother's calls."

John smiled. Psycho had been one of the movies he had more or less forced Sherlock to watch. If nothing else, the music had left some impression.

John was about to ask what his ringtone might be, when Sherlock spoke up.

"Mycroft received a text from Lestrade," Sherlock told him.

"Great, where is he?"

"He texted he was hurt, poison was used, he's in some sort of old clinic near the Thames and a train crossing a bridge could be heard. Furthermore he texted that there was a funny smell which you should recognise."

"Me? How would I know what he has smelt?"

"Come on, John, think. He wouldn't have texted 'ask John' unless he thought you would know what sort of funny smell."

"Yes!" John suddenly shouted. "And I remember something else."

Immediately he had Sherlock's undivided attention.

"Greg and I have been out for a beer some month ago. Actually weren't too far from here when we caught a funny smell. As it turned out the smell came from a factory that produces jelly beans."

"Where is that factory?" Sherlock asked.

"Look." They had just emerged between two buildings and now had a clear view of the Thames and the other side of the river. John pointed at a factory. A white plume was visible over one of its chimneys, drifting slowly over the Thames towards a dark area to their left.

"That must be it," John said.

"You said you remembered something else," the detective asked.

"Yes, right. That area down there housed an old laboratory and a clinic used before World War II by military. Eventually it was closed down. They demolished the building but as far as I remember there were several floors below the ground."

"Maybe the laboratory isn't as closed down as we think," Sherlock deducted.

They had reached the chain link fence that went all the way around the area.

Hearing a car approach, they ducked behind some rubbish containers, but as it turned out it was Stacy. She switched off the car's headlights and motor, and inched the last 100 yards to the threshold by letting her car just roll. When she had come to a complete stop, the car was approached by both men. Stacy hopped out and pulled them away from the car.

"Don't come any closer. The dogs might get excited and start barking."

They walked away for a few yards before telling Stacy what they knew.

"Shouldn't we wait for backup?" she asked.

Sherlock shook his head. "I'm certain backup is on its way. My brother undoubtedly traced my phone, and is sending over his men as we speak. We better hurry and try to get Lestrade out before they arrive.

"I'll make an opening in the fence. You go get your dog."

Stacy went to the car and came back a minute later with Dobby who looked eager to start whatever job he would be given.

"Before we go in, I have to prepare you," Stacy said. She pulled up a small bottle of lotion with a faint smell.

"Put some of that on your hands and faces. I trained Dobby to recognise it as the scent of the good guys."

"Good idea," Sherlock muttered. It was a known fact that police dogs couldn't distinguish between perpetrator and fellow police officers, and the latter therefore got bitten quite frequently when a police dog was unleashed.

Now that they were properly prepared they entered the area and went looking for an entrance to the building.