After Mycroft had left, Lestrade stayed a few minutes longer, obviously apprehensive about tomorrow. Mrs Hudson muddled around in the kitchen, clearing away tea cups. Getting up to leave, Lestrade glanced at the journal that John had held throughout the entire conversation, and nodded at it. "He was a good man, in the end, wasn't he?" John looked up to Lestrade from his seat, his eyes wide. Lestrade paused for a moment, and then gave John a knowing half smile. "Well, in his own way." The statement produced an unexpected flood of emotion in John, who was momentarily overcome by pride for Sherlock and heartache that his most noble endeavour had been his last. He tried desperately to swallow the lump in his throat. Lestrade patted him on the back, and excused himself. Overhearing the conversation, Mrs Hudson quietly wiped away tears in the kitchen.
John had not been able to sleep that night, partially because being in Baker Street once more made him a little anxious. Mrs Hudson had gone to bed after Mycroft and Lestrade had left, but had pushed a bottle of wine into his hands before leaving. He had insisted he was fine, but accepted it anyway.
Twenty minutes later and holding a glass of wine, he peered into Sherlock's old room. He had only meant to just look, but he let the door swing open, and the light from the hallway cast long shadows over the boxes, which were erupting with glassware and papers. He slowly walked into the room, and ran his hand along a distillation apparatus rather forlornly. He spied the familiar microscope which his friend had undoubtedly acquired through illegitimate means, and toyed with a 500 mL round bottom flask absentmindedly as he sat down on the bare mattress of the bed.
Sipping his wine, he smiled at the periodic table on the wall and the chart of the Lyman series for several elements—a series of transitions and ultraviolet emission lines which illustrates the quantization of energy in atoms.
He had soon felt overwhelmed by Sherlock's room and had retreated back to the living room. John was not sure what he had expected to feel by going in there, but he had just wanted to see it again. He pulled one of Sherlock's books off the shelves in the living room and began reading it. It was a biography of Lavoisier, the French chemist. The books had all been left on the shelves, though they were arranged much neater than before. One of the shelves that had been dipping severely before had been replaced.
John realized then, by looking at the new book shelf, that Mrs Hudson was acting more like a grieving parent than a landlady. He supposed he had always known how she felt about Sherlock, but the new shelf made him feel guilty for leaving her, as much of a wreck as he had been at the time. She had been keeping the living room much like it had been before Sherlock had died, or rather faked his death and took off dismantling an international ring of criminals in order to save their lives, damning his reputation.
Being unable to focus on the biography, he sighed and picked up the journal again. He had already read it through once, but he was still amazed at it. Sherlock had kept it for him. It was filled more with explanations of his deductions and processes—an illustration of the artist at work— than with any sentimentality, but that was to be expected. A journal of Sherlock's overflowing with sentimentality would be an alarming thing indeed. Still, it was a comforting object. Sherlock knew how much John liked to hear about his cases before they had met, and knew John would be interested in the details of his adventures whilst deceased.
He flipped over the entries regarding the case about the agent in the chemistry lab in Marseilles. Sherlock had been brilliant. He had acquired a job as a lab technician, and posed as a university student from rural France. This had been done to eliminate any suspicion of a strange accent in Sherlock's French, which was remarkably fluent.
The details of Sherlock's entries were specific enough that if John wanted to, he could write up the case. Sherlock had remarked before that he should turn his collection of blog posts into "real writing". At first John had been offended, but had eventually acquiesced. He had yet to start these actual writings, because he had been busy at work and found it painful to revisit the past. He had found it necessary, in the wake of being shot at, to take a few weeks off work, and wondered if he should not start taking notes again.
He smiled at the open page in the journal: it was a diagram of the lab, with labels of where chemicals were stored and how much of everything there was. There were a few circles in red ink on the diagram, and underneath, in Sherlock's excited writing, which was messier than usual, was an exclamation, "A drum of toluene is missing today!" He imagined Sherlock clapping his hands in glee at this.
The entry continued on the next page: "I have also discovered that a few litres of sulphuric and nitric acid are missing as well. Any university student in an organic chemistry class would know [Not exactly, John thought] that these are the common substances used in the synthesis of trinitrotoluene—TNT. Chemists make wonderful criminals, John. They have the power to simply make what they need, be it poison or explosives. They have the power to manipulate atoms to do their bidding, and easy access to all of the necessary instruments and materials. They are intelligent. Oh yes, the chemists! They make my work so much more interesting." Here, John wished he had been there to glare sternly at him until he realized he was being insensitive. Not that it would have done any good, of course.
"Today, I will hide the remaining toluene, because Louis will need it for his recrystallization tomorrow. I should be able to observe who looks the most uncomfortable when he goes around asking for it. He has a very mean temperament when he cannot find his chemicals! I daresay the criminal is obviously not Louis, because he is far too careless with his lab notebooks and locker keys. I hope that I will be able to spot the suspect by his hands and arms. I am looking for a canary."
John could almost feel his friend's excitement in the next entry: "The man with the yellow-stained hands is undoubtedly our criminal. Painting, ha! He has a much more sinister agenda than that, I think. I should maybe explain, though perhaps you already know, John. Trinitrotoluene is toxic, and when one handles it with the bare hands for a prolonged period of time, a yellow discolouration of the skin occurs. The factory workers who made it during World War I experienced this phenomenon, and were dubbed 'canary girls'. Well, I have found my canary."
John smiled at this, and closed the journal. Extraordinary, he mused, and wondered at the racing of his heart after reading the entry. He missed it. He decided that it would be a shame if he did not write up Sherlock's cases properly, because he owed his friend the restoration of his reputation at least.
He then frowned, remembering something from the Lavoisier biography. He flipped through the pages, and saw a sketch of a canary being placed inside a glass chamber. Lavoisier had been a brilliant and creative scientist, who performed research in identifying gases, a remarkably difficult business. There were a few standard tests that he had implemented, one of which was placing a canary in chamber, and observing what effects the gases evolved over the course of a reaction had on it. Sometimes, the birds perished. "Poor sod," John commented looking at the picture of the bird trapped in the vessel. Yawning, he closed the book and swung his legs onto the couch, and finally drifted off to sleep.
The next morning, as John walked down the street, he received a text from Lestrade informing him that he had been able to acquire a few officers to help follow this lead into the whereabouts of Ronald Adair's murderer. The existence of the journal had been kept between Mycroft, John, Mrs Hudson and Lestrade so far. Lestrade figured that the agents following John could have reasonably been found out without the journal. Mycroft had been helpful in that regard, though decidedly not in regard to sparing John from emotional distress.
His phone beeped again: "I have them in sight. Proceed to the next step—MH." Though Moran's agents would have maybe recognized police and government agents tailing them, they would not be looking for Mycroft Holmes, perhaps only for the simple reason that Mycroft Holmes did not involve himself in legwork. Lestrade's backup was currently on standby until they were able to pinpoint a location for Moran.
John, soothed a little by the presence of his gun in his waistband, quickly began to make preparations for the next part of the plan: lose them. Preferably without getting killed. Hopefully they would then try to make contact with Moran, either by phone, in which case Mycroft's valuable resources would be helpful, or even better, they would return to Moran in person to receive further instructions.
John hailed a cab. He gave a predetermined and arbitrary address, and when he reached that address, walked through a massive crowd and quickly hailed another cab, giving another predetermined address. He did this once more. At every checkpoint, he confirmed his location with Mycroft or Lestrade. They were alternating being present at his checkpoints, looking for the point at which Moran's agents would lose John.
He took the tube for a short distance, and then got off at the next stop. He headed for a crowded bookstore, pulling out his phone. As he was walking, someone ran into him quite hard, knocking his phone out of his hand. It scattered down the pavement. The person who ran into him must have been carrying a lot of books, as at least seven had ended up on the sidewalk as well. John leaned down to pick up his phone, as the old man who had run into him scowled and told him to "bloody well look out," and John glared, muttering, "Yeah, yes, alright," as he leaned over to pick up the books and give them back to the decrepit individual. John glanced at the titles, and saw one on poisons from plant derivatives, and another on Impressionism. He frowned, wondering about the eclectic selection. Before he could ponder any further on the matter, the man snatched the last book—something by Francis Bacon—out of his hands and limped away, muttering to himself. John rolled his eyes, and continued toward the bookstore.
Inside the bookstore, he ducked behind tall shelves of books, and the aisles were packed with people waiting for a copy of a new release. He discretely pulled a pair of glasses and a hat from his jacket. He then took off his jacket, revealing a blazer underneath. Discarding his jacket on the floor, he put the glasses and hat on, and quietly began to extricate himself from the mob of people. He saw Mycroft's assistant in the line waiting for him, in her usual black dress. He wasted no time in burying his face in her neck and grabbing her around the waist. They walked casually outside together, acting like a couple on a date.
She led him to the curve. A sedan appeared at that moment, and she and John tumbled in. John's phone beeped: "You've lost them. They are still in the bookstore—MH". John released her and leaned back in his seat, exhaling in relief. He took off the hat and glasses, and waited anxiously to join Mycroft and Lestrade.
He was dropped off at the edge of London in a deserted parking lot an hour later. Mycroft was waiting for him, and silently handed him his jacket. "Oh, cheers." John said, taking it and putting it on.
"Lestrade went ahead with two officers. We're to meet them up." John nodded, feeling the weight of his gun again.
They found Lestrade and his backup, and John spotted the two men immediately. It was beginning to turn dark, which made their concealment much easier.
The two men stopped at what looked like a group of abandoned flats in old brick buildings. The neighbourhood was well-enough deserted, and most of the windows John observed seemed to be boarded up. Broken glass littered the ground, and graffiti marked the dilapidated walls of the buildings.
They walked quietly to the edge of a building and peered around the corner. The two men entered one of them, and Lestrade indicated for his two officers to go around the back. Lestrade, John, and Mycroft approached the front cautiously. John and Lestrade pulled their guns. Mycroft strolled ahead to the door, pushing it back slowly. He paused for a moment to observe the lock. It had been changed recently, but was turned around, though a key could not be used from the inside. There was also a large combination lock on it, which was open. Frowning, he pushed the door further open, noting that it seemed quite heavy. His eyes narrowed at this, but he continued into the flat, moving silently. John and Lestrade followed him.
They turned down a dark hallway, with dirty, peeling walls. Mycroft turned into the living area, and stopped suddenly, observing the ancient room. A window had been put in recently. In fact, all of the windows he had observed on this floor were new. He looked around the flat urgently. It was completely silent. His eyes widened, and he turned suddenly to John and Lestrade, and whispered, "Get out!"
"What?" Lestrade asked.
"Get out!" Mycroft yelled, and began running toward them, shoving them in the direction of the door. "Tell your men to get away from the building!" He ordered Lestrade as they rushed for the door. As Lestrade gave the order on the radio, they came to the door, which they had left open. It was now shut. John tried the knob, and discovered what Mycroft already knew. It was locked. Mycroft had taken off down the hallway and into the kitchen.
The refrigerator had been pulled away from the wall, and strapped to the back was a bomb. He turned around and exited the room.
"They aren't replying," Lestrade informed them.
"They're probably dead," Mycroft replied over his shoulder, walking past Lestrade.
"A trap," John breathed in disbelief, and ran after Mycroft. "What do you think is going to happen?" Lestrade yelled after John, following him.
Mycroft came back, and exhaled heavily. "A bomb will go off." John's eyes snapped to Mycroft. "It's in the kitchen."
"We're going to get blown up?"
Mycroft didn't reply, and instead watched Lestrade aim and fire at a window. It absorbed the bullet.
"Polycarbonate," John commented. Mycroft nodded at him, unsurprised. Lestrade lowered his gun.
"They didn't want to kill us unless we came after them." Mycroft whispered to himself.
John heard, and studied his face. "Sorry, what?"
"Ah, of course!" He continued to himself, ignoring John, "It's going to happen very soon. They thought it would take us longer to figure it out and come back to the door. They wanted us to know what was going to happen to us, and why. Yes, interesting. They think we know—," he stopped suddenly, noticing John and Lestrade were staring at him.
"What about breaking down the door?" John suggested, as he and Lestrade ran over to it.
"No, I don't think so." Mycroft replied, not moving. He spied a figure moving outside. "Get away from the door!" He hissed at them.
John and Lestrade exchanged a look, but obeyed. They heard a crackling noise, and backed into the living room with Mycroft, concealing themselves behind the wall.
An explosion from directly behind the wall made Lestrade jump away, and John leapt in front of Mycroft, who had failed to move, pushing him down and attempting to protect him from the blast. Lestrade had hit the ground, covering his head. After it was over, they looked around, dazed momentarily. The blast had been too small.
"That was not—that couldn't have been the bomb," John mumbled, perplexed that he was still alive, and eyeing Mycroft, who was lying below him, for injuries. Mycroft suddenly jumped up, pushing John out of the way, and ran through the dust toward the source of the blast.
Lestrade and John paused for a second, and then leapt up after him. Coming around the corner, they ran straight into Mycroft's back. Mycroft was just standing in front of the explosion point, with dust and smoke swirling around him. Peering around his body, John and Lestrade found that the door was gone. Mycroft stood in front of the opening in the wall, staring. They exchanged a sideways glance, then shrugged, and walked towards it, grabbing Mycroft by the elbows and dragging him outside.
Looking around, they saw no indication of what had caused the door to be blown away. John motioned for Lestrade to take Mycroft away. "Get him out of here! We don't know when it's going to detonate. I'll look for your officers." Lestrade hesitated a moment. "Go!" John ordered, running around back. Lestrade nodded, and began running to safety with Mycroft.
"Be quick about it!" He yelled over his shoulder. When John reached the back of the building, he whirled around, confused. They were gone. He ran around the other side of the building, but could not find them.
"Over here!" Lestrade yelled, about seventy metres away from the building. "They're still alive!" John furrowed his brow, but glad to get away from the building, sprinted toward Mycroft and Lestrade. When he had gone about ten metres, a massive explosion knocked him to the ground. He felt the searing heat wave crash over his body, and remembered nothing else.