A.N.: *WARNING! SPOILERS FOR SERIES 3 IN THIS AUTHOR'S NOTE* I know that this is supposed to fit in with canon, and based on what Mycroft said in HLV, the fandom is going kind of crazy about how there's a third Holmes brother out there, and in this chapter, Sherlock says he's only got one brother. I think that the third child is a sister. There was no reference to the gender of the third sibling, and I just don't think it was a boy.

Warnings: References to drugs

Disclaimer: Don't own Sherlock

Chapter 2 – In Which a Transgression is Forgiven

Greg Lestrade had had a bad day.

He had been getting nowhere with the serial killer suicide case, and Sherlock was being as annoying as ever. He was showing off a lot more on this case than he had been lately, though Greg guessed that was because he had a new audience – a particularly adoring new audience.

When Sherlock had turned up at the Brixton scene with John Watson, Greg didn't know what to think of him. He certainly had to be something special if Sherlock was insistent on having him there, but after four suicides – even with one that now had a note – he was desperately tired and just wanted to get home.

Unfortunately, that hadn't been an option for him, and he had been forced to do a fake drugs bust at Sherlock's new flat – which was even further away than his old one had been, an annoyance in and of itself – which the detective had then wandered off from.

Now, he was standing at the scene of another crime – this time with the killer being the victim – which Sherlock and John were leaving the mess of with him.

When Greg had learned the particulars of the shooting, and Sherlock had given him his predictions about the shooter, he had known almost on instinct who had killed the cabbie. Not that Greg said anything; he didn't particularly want to get the first friend that Sherlock had made in several years jailed after they had only lived together for a few hours. Not only that, but Greg had come to like John since their initial meeting in Brixton, and he personally didn't want to see him in prison.

Unfortunately, he noticed that Sherlock and John had stopped a few feet away from the police tape, and were talking to someone. There was two people standing before the Baker Street pair – a man and a woman. Greg's heart dropped as he thought about who they could be talking to: he could think of only one man whom Sherlock would stop in his tracks to talk to after solving such a difficult case, and that was the one man whom Greg really didn't want to see after the day he'd had.

The man with whom Sherlock and John were talking turned to face him, and their eyes caught each other from either sides of the yellow police tape.

Greg's suspicions – and fears – were confirmed.

Mycroft Holmes.

Oh.

Shit.

Greg had learned of the elder Holmes' name when Sherlock had been going through withdrawal. The detective – who, at the time, was not yet really a detective, but he was close enough to being one that he deserved the title anyway – had had periods where he was delirious, unsure of where he was or who he was with.

One absolutely freezing night, when the detective had been suffering from a fever that had called for Greg to hold ice packs against Sherlock's clammy forehead and marvel at how they melted and dripped despite the cold outside, Sherlock had seemed to revert to childhood. He kept mumbling about pirates and the seven seas, and at one point he had called Greg 'Mycroft'.

Greg, knowing that it was probably best to play along with him, had pretended to be this person – whoever he was. He didn't have to wait long for the delirious detective to reveal to him just who this person was.

"You're the best brother ever," he had drawled as he absentmindedly ran a hand through Greg's hair. "Not jus' cause you're my only brother. Because it's true."

The real Mycroft – whose speed at attaining information bordered on the terrifying – knew instantly what had occurred between the aspiring detective and the detective inspector, and didn't take particularly well to Greg finding out what his name was. The next time Greg had seen Mycroft, he had made it clear that under no circumstances was he to tell anyone exactly who he was.

Greg had never been particularly scared of Mycroft. He recognised his authority much like a student recognises the authority of a teacher, but he was one of those teachers that, regardless of the power he held, he couldn't seem to be able to take seriously. While he was well aware of the danger that Mycroft could possibly cause him, he felt safe in the knowledge that, as long as he was still important to Sherlock, the elder brother wouldn't touch him.

That was, unless he didn't keep his word that he had given in the warehouse all those years ago.

Greg watched the scene from a distance as Sherlock and John walked off with smug swaggering strides, and Mycroft and his assistant watched them. Greg thought about trying to find somewhere to hide, where he wouldn't be at the receiving end of a scolding from the elder Holmes. He dismissed that action as cowardly; he was a detective inspector, not a naughty schoolchild, and besides, even if he could evade Mycroft tonight, the man would find him sooner or later and tell him what he wanted to say.

As Sherlock and John disappeared from view, Mycroft and his assistant turned around. The former began to walk over to the police tape, while the latter stayed behind, still typing on her phone. Even so, Greg had no doubt that she was paying very close attention to all that was going on around her.

Greg watched and waited as Mycroft lifted the police tape and ducked under it; an officer nearby seemed to think about telling him that he couldn't do that, but – presumably realising just how important the man who had just passed him was – drifted away again and quickly got on with something else.

Just as Greg had suspected, Mycroft walked straight up to him and tapped his umbrella on the ground with an air of finality, his features fixed in a disappointed scowl.

"Good evening, Detective Inspector," he drawled in that smooth voice of his.

"Evening," Greg nodded, not wanting to say his name out loud in public for fear of retaliation – he was in enough trouble already.

"How much do you know of what transpired here tonight?"

Greg shifted uncomfortably, finding it difficult to meet the man's eyes. "Well," he began slowly, trying to find a way of telling Mycroft everything he knew that still painted him in a positive light. "The killer turned up at Baker Street earlier this evening, and Sherlock went with him. They came here, they talked, the killer shared information about how he was killing his victims and showed Sherlock the pills that he had been using."

Mycroft nodded. "One poisonous pill, one neutral pill. And then?"

Greg opened his mouth but no sound came out. He stood there flapping like a fish before he mentally slapped himself around the face and continued in a voice that was slightly squeakier than he normally would have talked. "The killer was shot from another part of the building. He died a few moments later."

"And what about the pills?"

Greg gulped. "S-sorry?"

Mycroft sighed and rolled his eyes. "The pills. There was one poisonous and one neutral; you have already said that the killer showed both to Sherlock. What happened to them?"

Greg cleared his throat, if only to buy more time to come up with a story with enough truth in it that he could still get out of this conversation without feeling completely stupid. "Well, Sherlock had them both."

For a moment, Mycroft didn't react. His lips thinned into a sharp line across his face, and he looked down at Greg with hooded eyes, a glare that sent shivers down the Detective Inspector's spine.

"If it were not for this shooter," he began in a low, dangerous voice, "would my brother have died tonight?"

Greg had known this was coming since he had first seen Mycroft across the scene. He still hadn't found an answer that would suit them both, so he decided to go for the truth.

"I-it's possible," he admitted, interrupting Mycroft before he could rebuke him. "It was only a fifty per cent chance, though! And knowing Sherlock, he had the right pill anyway-"

"We cannot be sure of that though!" Mycroft snapped. He took a deep breath, as though calming himself down. "You promised you would look after him."

"He ran off!" Greg exclaimed, throwing his arms out to the side before dropping them again.

Mycroft said nothing, his eyes moving across Greg, deducing. It was a gaze that Greg recognised, one that both of the brothers had given him, but that didn't make it any less uncomfortable.

"Alright," he conceded slowly.

Greg blinked. "I'm sorry?"

"You cannot be responsible for everything." Mycroft straightened himself up to his full height. "Good evening."

He turned and began to walk away, leaving Greg standing in the middle of the road feeling utterly confused.

"Don't you have some work to do?" Mycroft called back, swinging his umbrella as he made his way back over to his assistant.

"Who was that?"

Greg was caught off-guard by the new voice that suddenly appeared on his right. He turned and saw Donovan watching the strange man leave.

"Er…" Greg hummed, "just… someone. Don't you have some work to do?" he asked, turning fully to her.

She raised her hands in mock surrender and backed away.

"Alright, alright. Suit yourself."

When Greg turned back in the direction that Mycroft had left in, he, his assistant, and the slick black car, had all disappeared.