While Sherlock took Dimmock to Bart's morgue to prove to him that Lukis and Van Coon had been part of a Chinese smuggling gang, John and Morgan waited back at Baker Street. As John went to take off his jacket he remembered the gun in the inner pocket.

"Oh, here," he said as he took it out, offering it to Morgan.

"Thanks." She went upstairs and placed it back in her bedside table drawer before grabbing some clothes and jumping into the shower. As the water washed over her, it felt like it was washing away the night's events. It instantly calmed and refreshed her. She pulled on a pair of loose track pants and her favourite oversized sweater.

When she went back downstairs, John was seated in his armchair, holding a mug full of coffee. He picked up another mug sitting on the small side table and offered it to her. She accepted it with a thanks and sat down in her father's chair. She normally wouldn't drink coffee so late but if Dimmock consented to giving Sherlock Lukis's and Van Coon's books, they were going to have a late night.

"I'm sorry," John suddenly said.

"What for?"

"Leaving you in the museum," he explained. "I should have stayed with you and Soo Lin."

"John, don't be sorry. If you hadn't of gone out there, I would have."

"But you and Soo Lin in were in danger and I-"

Morgan could tell what John was thinking so she cut him off. "John, you are not to blame for Soo Lin's death," she said with force. "There's only one person to blame."

John nodded but she could still see the guilt in his eyes.

The door downstairs suddenly slammed shut. A moment later Sherlock bounded up the stairs into the flat.

"How'd it go?" John asked.

"Good." Sherlock shrugged off his coat and hung it up on the hooks on the back of the door. "We'll be getting the books from Lukis's and Van Coon's apartments soon." His scarf joined his coat on the door before he walked between John and Morgan to stand in front of the fireplace. "It's not just a criminal organisation," he said. "It's a cult. Soo Lin's brother was corrupted by one of its leaders."

"Soo Lin said the name," John said.

"Yes. Shan. General Shan."

John sighed as he placed him mug down on the side table. "Were still no closer to finding him."

"Wrong," Sherlock said instantly. "We've got almost all we need to know." He walked out to the middle of the living room and turned to face the pair, still seated in the armchairs. "She gave us most of the missing pieces. Why did he need to visit his sister? Why did he need her expertise?"

"She worked at the museum," John answered.

"Exactly."

"An expert in antiquities," Morgan said.

"Valuable antiquities. Ancient Chinese relics purchased on the black market. China's home to a thousand treasures hidden after Mao's revolution."

"The Black Lotus is selling them," John said.

Morgan watched her father's face change as a thought crossed his mind. He strode over to the table and sat down, opening his laptop and brining up a search engine. She watched over his shoulder as he typed 'Chinese antiquities sold at auction'. John stood up and walked over to see what he was doing. Morgan joined him, standing behind her father.

"Check for the dates," Sherlock mumbled as he scrolled through an auction site. "Here." He'd stopped on a page showing 2 Chinese Ming Vases. "Arrived from China four days ago." He looked to see who they'd come from only to see a name wasn't given. "Anonymous. The vendor doesn't give his name."

"'Two undiscovered treasures from the East'," Morgan read off the website.

"One in Lukis's suitcase and one in Van Coon's," John said.

Sherlock tried another auction page. "Look, here's another one. Arrived from China a month ago, Chinese ceramic statue sold for £400,000."

"Look, a month before that," Morgan said as she pointed to another auction on the screen. "Chinese painting, half a million. All of them from an anonymous source."

"They're stealing them back in China and one by one feeding them into Britain."

John went over to his coat and pulled out Lukis's diary, flipping through it. Sherlock pulled out a copy of Van Coon's diary his secretary had given him. John looked at them both. "Every single auction coincides with Lukis or Van Coon travelling to China."

"So what if one of them got greedy when they were in China? What if one of them stole something?"

"That's why Zhi Zhu's come," John said.

A knock at their flat door made them all turn. "Sorry," Mrs Hudson said as she stood in the doorway. "Are we collecting for charity Sherlock?"

"What?"

"A young man's outside with crates of books," she said.

Sherlock smiled. "Let them up."

Mrs Hudson grumbled as she walked back downstairs. Minutes later there were policemen bring in crate after crate, stacking them all around the living room. The policemen looked less than happy to be lugging heavy crates of books into a strangers house in the middle of the night. Morgan sat in her father's armchair, watching the living room slowly fill up until there was barely any space to move. Unfortunately for them, both Lukis and Van Coon had owned a mountain of books which was going to make finding the right book difficult.

She'd just finished making another cup of coffee when the last crate was brought in.

"So the numbers are references," Sherlock said as he stood amongst the crates.

"To books," John said.

"To specific pages and specific words on those pages."

John nodded. "Right, so…15 and 1, that means-"

"Turn to page 15 and it's the first word you read."

"Okay, so what's the message?" he asked.

"Depends on the book," Sherlock said. "That's the cunning of the book code. It has to be one that they both own."

John sighed as he glanced around at the piles of crates. "Ok, fine. This should take too long should it," he said with a touch of sarcasm.

Sherlock ignored his words as he opened a crate and starting sorting through it. Morgan handed John a cup of coffee which he gratefully accepted before he grabbed a handful of books and took them over to the table. Morgan started with the crates at the other end of the living room.

Dimmock walked into the living room, holding up a small evidence bag. "We found these at the museum. Is this your writing?"

"Er, we hoped Soo Lin could decipher it for us. Ta." He took the evidence bag from Dimmock, leaving him standing awkwardly in the middle of the room.

"Anything else I can do?" he asked, reluctantly adding, "to assist you I mean?"

"Some silence right now would be marvellous," Sherlock answered curtly as he continued searching through a crate.

Dimmock looked to John with raised eyebrows, who apologetically smiled. After standing there awkwardly for a few seconds, Dimmock turned around and left the flat.

It didn't take Sherlock long to find the first two matching books. He flipped to the fifteenth page and read the first word; cigarette. Snapping the book shut, he picked them both up and dumped them next to John on the table.

After half an hour Morgan's legs were already aching from standing so she picked up the crate and put it on the coffee table so she could search through it while sitting on the sofa. From her new position she couldn't see John and Sherlock but she could still hear her father angrily snap books shut.

The hours ticked by and the searching continued. The only sounds in the apartment was the sound of crates opening and pages turning. And the occasional yawn.

John discovered Morgan asleep on the sofa when he'd gone to ask her if she wanted another cup of coffee. He sighed, envious of her peaceful sleep. All he wanted to do was go upstairs and crawl into his bed but he was determined to keep going until they found the book. He owed it to Soo Lin.

He resumed his seat at the table after grabbing another pile of books. As he looked at the pile of books at his feet then at the crates around the room, he realised they'd barely made a dent. What he thought might take hours was going to take days.

A small beeping sound echoed through the silent flat. It took John a moment to realise it was the alarm on his watch. As he switched it off and looked at the time, he let out a groan. A quick glance over his shoulder at the window and the light streaming in confirmed it was morning. John placed his head in his hands. He had to be at his new job in less than an hour.

He could already tell it was not going to be a good day.

Morgan groaned as she woke up. All she wanted to do was roll over and fall back asleep but she knew she shouldn't. Reluctantly she opened her eyes and sat up on the sofa. She was greeted by a wall of crates. There was still so many they'd get to get through.

She stood up and stretched. Her father was still searching however John's seat was empty. It took a moment for her still sleepy mind to realise why. It was his first day at work. She wondered how he was going considering he'd only had 5 hours sleep in the past 2 days.

After showering and having something to eat, Morgan walked back into the living room and sat down at the table.

"Nothing?" she asked, even though she knew the answer.

"Nothing," Sherlock confirmed.

"What if the book isn't here?" she asked.

"It has to be here."

"So what, we're just going to spend another night searching crate after crate?"

"Oh no," Sherlock said. "We're going out tonight."

Morgan frowned as she heard her father's words. "Out? Where?"

He reached into his pocket and produced a strip of paper, the paper he'd ripped off the wall two nights ago. Morgan glanced down at it as he handed it to her. It was an ad for a Yellow Dragon Circus, performing in London tonight.

"A circus," she said incredulously. Sherlock was staring at her. It took her a second to deduce why. "Oh." The circus was just a front. Zhi Zhu, General Shan and the Black Lotus workers needed to come to London to recover what was stolen from them. Exit visa are hard to come by in China which meant they needed a pretty good, legitimate reason for leaving. She handed the paper back to him, saying, "I guess we're going to the circus."

Sherlock slipped the paper back into his pocket and returned to the crate he was searching through. Morgan walked over to the sofa and found the crate she'd been on when she had fallen asleep. She sat down on the sofa and starting going through it. She had a spark of hope every time she found two matching books which quickly diminished when she opened it to the fifteenth page and the first word was something like 'a' or 'the'.

John came home after 5 with a huge grin on his face. He popped his head in and asked how they were going before going upstairs to get ready for his date.

Sherlock snapped shut the lid of a crate as his frustration grew. He started muttering, "A book that everyone would own,", while pulling books, like the dictionary and Bible, off of the shelves behind him.

John walked back into the living room after having showered and changed his clothes.

"I need to get some air," Sherlock said as he ran his hands through his hair. "We're going out tonight."

"Actually, I've got a date," John said with a hint of pride.

"What?"

"It's where two people who like each other go out and have fun."

"That's what I was suggesting," Sherlock said, confused.

Morgan stifled a smile at her father's ignorance while John said, "No it wasn't. At least, I hope not."

"Where are you taking her?" Morgan asked.

"Cinema."

"Uh," Sherlock said. "Dull, boring, predictable." He walked out from behind the crates and reached into his pocket. "Why don't you try this?" He handed John the Yellow Dragon Circus ad. "In town for one night only."

John let out a chuckle as he looked at it. "Thanks but I don't go to you for dating advice."