Another 'drugs bust' in 221B and Lestrade amuses himself by watching his officers going half-heartedly through the clustered mess in the flat. Previous experiences have taught them to open any boxes or cupboards with caution because nobody wants a repeat of Sergeant Miller's intestines incident. And today even comes with a special level since there are still glass shards and other debris lying around from the 'gas explosion' a few days earlier.

They've met the glaziers on their way in and Greg can feel the temperature in the flat going up, but it is nowhere near a level where anybody should only wear a t-shirt, pyjama bottoms and a nightgown as one of the flat's inhabitants is currently doing. But after more than five years of dealing with the mad genius the DI knows better than to utter his concern.

In fact the 'drugs bust' is even more fake than the previous ones, but the mysterious message on Sherlock's website as well as the detective's tendency to head straight away into trouble were worrying the DI and he was glad for some missing cold case files in the department so he could at least give a plausible reason for this field trip to Baker Street.

And he would never admit it out loud but it is quite entertaining to watch an irritated Sherlock pacing among the police officers with a dramatic swirl of his dressing gown and a huge air of annoyance. Although Lestrade knows to keep Sherlock's irritation at a certain level because John is nowhere to be seen and without him things can easily turn nasty.

"I don't have your files", the consulting detective snarls once again and interferes as one of the officers reaches for a bunch of paperwork which seem to contain everything from newspaper clippings to discarded maps.

"Well, if you don't, great detective, why don't you solve the mystery of the disappearing case files and we'll leave you to your afternoon tea."

To be honest Lestrade is pretty sure that they won't find the files in the flat. Usually they only notice that Sherlock has stolen some paperwork when he brings them back along with at least a list of suspects. And the man had been occupied for the past days with the mysterious 'bad Samaritan', so there was no need for any boredom elevating measures.

From shared stories over a pint or two with John Greg can identify older signs of Sherlock's boredom in the flat. The kitchen area is generally a mess of random experiments, the living room table has a new design of carved out lines and the DI avoids thinking too hard about the smiley on the wall and what looks like bullet holes. There are certain mental paths you shouldn't follow around Sherlock.

Another bout of impatience returns Greg's attention back to the detective. The man always uses his complete body to express himself and this demonstration of frustration comes with extravagant arm failing and ruffling of his own hair combined with another command to leave him alone. Even Sherlock's clothes seem to join in the dramatics when worn by him because the gown slips with an elegant swoosh from his shoulders all the way down to his forearm before it is pulled up again.

But even after Sherlock is all covered up again Greg's eyes are fixed on his elbow. Because the dressing gown not only revealed fair skin on surprisingly well-toned arms but also a little red mark contrasting against the pale ton of skin. A mark that is too familiar from a past he had hoped they had buried years ago.

For a moment Lestrade can actually feel all of his thoughts coming to a halt before everything takes up speed again as if it wants to make a up for the lost moment, spiralling in a whirl of 'no' and 'not again'. He is aware that he loses his professional mask, has in fact lost it years ago when he had found a junkie high on cocaine in a filthy apartment.

He tastes bile in his throat and for the first time in years he fears they will find something because Sherlock consuming was always too lazy to hide his supply properly. Thank god, neither Donovan nor Anderson are here, a small relief that those who know him best and are most likely to identify the rise of panic in him refused 'to spoil a perfectly nice work-day with the freak'. He jumps up from the chair, trying to sound nonchalant as he orders an end to the search and waits impatiently for his officers to leave the flat.

Lestrade feels Sherlock's gaze on him, but he can't meet his eyes because he is afraid that those words that assemble on his tongue, words of anger and disappointment and horror, will stumble out before the others are gone. And for once Sherlock keeps his mouth shut, doesn't talk to him, doesn't require him to speak. Instead the DI listens as Sherlock makes a phone call to John, asking him to come home immediately.

Finally they are alone and Greg takes a steadying breath to look at the young man in front of him. Sherlock looks completely serious, evaluating him with those mercury eyes that see too much and sometimes not enough. His childish demeanour is forgotten and his tone is almost apologetic when he offers a silent: "It's not what you think. John will explain."

Even Sherlock's voice is not the self-confident baritone, but something less, something almost normal and Lestrade breathes out, feeling somehow bereft of his righteous speech and all of his thoughts of the last minutes are caught in a helpless "Sherlock". He has spent too much time watching Sherlock struggling with drugs, giving a detoxing junkie unsolved cases to occupy his mind. He has seen the trembling mess of this very man lying in his own vomit and he had been so sure that those days were over when he had regularly wondered if Sherlock was still alive.

A gentle touch brings him back to the present, standing somehow lost in a cluttered flat, unsure how to proceed, unsure how to respond to the mixed emotions and the obvious. Does he dare to trust? For the moment Lestrade allows Sherlock to guide him back to the seat and surprisingly a mug with tea is pressed in his hand. The hot temperature lets him flinch and when he looks up at Sherlock the detective stares at him a little bit stunned.

"Caring is not an advantage, Detective Inspector."

Normally, such a statement would provoke an argument from the DI but maybe he is still in shock from seeing the needle mark on the pale skin or the lack of vile in this statement so Lestrade ignores it in favour of a cautious sip from his tea. Sherlock settles on the sofa and they wait in tense silence. Two times the older man tries to form words but each time he is stopped by the younger one. "Wait for John; he can explain it better than me."

And maybe it is a sign of trust or desperate hope or simply idiocy despite the evidence that the DI waits patiently for footsteps on the stairs. He doesn't know how much time has passed, the flat has become a timeless place and the only indication that the world hasn't indeed stopped is the amount of tea that is gone from his mug by the time John arrives, worry deepening the lines on his face.

The doctor looks between the two detectives and only Sherlock's order "Tell him about the puncture" allows understanding to dawn on John's face. Lestrade sees the look they share, but he can't decipher it, excluded from a bond he never thought Sherlock being able to form. The consulting detective leaves, Lestrade listens to the bedroom door clicking and another silence settles in the living room.

The DI has no idea how to start this conversation, a conversation he should have with Sherlock and so he waits for John to begin. John who is currently running a hand through his hair, burying his face in his palm. Different emotions chasing their way across the doctor's face and although Lestrade can't identify all of them – his view is still blocked by John's hand – he is pretty sure he sees worry and guilt among the array of facial expressions. Especially the latter transforms the knot in his stomach to something that seems far too solid to ever vanish.

"It's not what you are thinking", John starts and Greg doesn't know how often he has heard this sentence in his life only to confirm later that it was exactly what he was thinking. He has heard it from suspects and his own children and somehow in his mind its original meaning has morphed to an admission of guilt. And suddenly anger is the only thing left form his emotional turmoil and he wants to shout at John, wants to shout at him for helping an ex-junkie to get high again.

An army doctor who should know better than to turn this brilliant, maddening, infuriating genius back to the shadow of himself with sweaty skin, too dilated pupils who didn't care if he lived one more day. In the end he doesn't shout, but it is a close call. With forced calmness and a voice roughened by emotions and a constricted throat he answers: "You don't know what I'm thinking John. You know nothing, you haven't seen him."

"I may have not seen the same as you, but I have seen him craving the next shot."

The hint of annoyance in John's statement feeds Lestrade's anger as well as another unwanted memory of an almost translucent Sherlock in a hospital bed on white sheets.

"And you decided to give him a shot? Is it that what you want to tell me? Because he needed it, you decided to give him a shot?"

His anger is answered by anger and hurt and the experienced interrogator sees the attempt at control: "You think I would help him? Do you really think that of me? Are you mad? I'm a doctor. I help people."

And Lestrade realises that he might just have lost a friend (and it stings), but he pushes the disappointment back in the part of his brain that is reserved for private matters.

"Then explain, just explain. Would you finally explain?"

They stare at each other for long moments, brown eyes meeting blue ones, both sets hardened by restrained anger, tinted with worry. Greg couldn't tell how long they were silently challenging each other, before John retreated, his gaze turning inwards, accompanied by a soft sigh.

It is obvious that now it's the doctor's turn to visit some unpleasant memories, but Lestrade just waits. He is no longer the friend; he concentrates on his lifelong training as a police officer. He has long learned the mental dance with a suspect, not always the same, but familiar enough. He knows when to outwait his opposite, when silence will lead to confessions or information. A slight nod ends John's contemplation and when he mentally returns to the living room and to Greg his eyes are clear.

"Do you know this one scene in Harry Potter, when the mother tries to kill some kind of monster that shows you your biggest fear and she sees everybody dead until one of Harry's uncles stops her and takes over?"

Lestrade nods, he doesn't bother with corrections, doesn't want to interrupt the train of thought.

"She fears the whole time that her family will die sooner or later", John continues. "She is caught up in this vicious circle until someone else stops her." He takes a deep breath. "I know that Sherlock always said he took the drugs out of boredom, but I think it was his way to stop thinking, to get out of one of those loops. He had nothing else."

John catches his eyes and Lestrade feels himself nodding again. Sherlock had never seemed outright lonely, never seemed to look for a companion, but he had always been alone.

"He came to me, last night, shoved his kit in my hands and ran away from it. I went after him; I thought … I've never seen him like this. It was clear what he wanted, what he craved, but he had to know that I wouldn't … Greg, I would never … " The doctor takes a deep breath and continues: "So, I took a syringe from his kit and injected him with distilled water. I thought about calling you, but I didn't know how he would react. In the end I didn't want to leave him on his own."

Lestrade takes the words in, still focusing on his training, on staying neutral, impersonal, evaluating the information John had provided. The trained police officer of course notices the lack of detail on Sherlock's kit and the return of familiarity, but ignores it: "Placebo effect?"

"How effective is a placebo if the patient is aware of it?" John counters and there is nothing of the former anger in it, only exhaustion and oddly enough relief.

"How often?"

"Just this once. And I don't think he has taken anything since I moved in."

Again, silence settles. It weighs different this time while Lestrade tries to come to terms with John's story. The man in front of him looks absolutely honest, but the DI knows what the doctor is willing to do for Sherlock and how remarkably well he acts as an innocent bystander. Until now John had protected the younger man from his own recklessness, from Lestrade's crew. His instinct tells him that he is telling the truth and it is no secret that the doctor admires Sherlock's mental abilities. For the moment this might be enough.

Lestrade is absolutely aware that he is also biased. He had considered John a friend and he cared for Sherlock – hell, he had sent his whole team away when there was a chance that this fake drugs bust might turn real – but right now it seems to be safer to stay on the professional side, to watch them a bit closer in the next weeks. John didn't tell why Sherlock suddenly needed artificial help to stop thinking, although it has certainly something to do with untold events from the night before. Maybe Mycroft might be a bit forthcoming with information, although he wouldn't bet on that.

There is nothing more he could do. Beside a puncture he has no evidence and sending his time away meant sweeping things under the rug. The anger and the initial panic are gone; the knot in his stomach smaller but still there as well as a new uneasiness. He is unsure what to say, a lecture seems out of place. He wants to offer help, but he still feels more like the DI and not like the friend not to see potential complications with that.

Slowly he takes his coat and settles for polite commonplaces. 'Thank Sherlock for the tea' and 'Stay safe' seem fitting. There is still tension between him and John and they watch each other out of the corner of their eyes when they make their way to the front door. A military nod is John's 'Good Bye' and then the door is closed behind him and Lestrade wonders why this seems so final. His mobile beeps with a new message on his way to his car.

Ask Sergeant Hopkins for the files. He wants to impress you. SH

And he can't help the impulse to look up at the windows of their flat and is not surprised to see them both watching him, standing so close together that the semidarkness molds their contours to one. Somehow this symbol of their closeness is not as reassuring as it was some days ago.