Author's note: I got the idea for this story from the epilogue to another story of mine, 'What Mary Knew' – they are of the same universe, but no need to have read it to enjoy this (although obviously I would love it if you did!)

Chapter One

The first time he met Molly Hooper, you could barely call it a meeting. In fact, if you'd ask him about it even later that evening, he would perhaps have vaguely recalled a ghastly Christmas-themed jumper under a lab coat, but very little else. Sherlock had called her in advance of their arrival at the morgue, of course, and Mycroft had been fleetingly puzzled as to why anyone might be at his brother's beck and call in quite that way, but the thought hadn't been important enough to stay with him.

So when, some several weeks later, Sherlock had spoken her name, told him that she would be part of Operation Lazarus – that she could be trusted wholly and implicitly – Mycroft had had to ask. To be reminded of who she was. At what point had a pathologist from St Bartholomew's Hospital become his brother's close confidante? He wasn't going to ask and Sherlock certainly wasn't going to tell him. But he had to take Sherlock at his word, and Molly Hooper immediately became part of the plan – not just part of it, but absolutely vital to it. It was on that day that Mycroft saw the real Molly Hooper, her strength, her intelligence, her steadfastness – and her devotion to his then-undeserving little brother.

And now, in the eyes of the law, Molly Hooper was his sister-in-law.

Mycroft scanned the room until his eyes came to rest on the happy couple – so happy it should be sickening, but he can't quite bring himself to feel that way. Sherlock, he could see, had no interest in 'working the room' on his wedding day, only wishing to keep his new wife to himself until enough time had passed for Molly to agree that they could leave without causing offence.

It was only once Molly Hooper became involved in Sherlock's 'suicide' that he felt the need to find out more about her. Background checks showed up nothing remarkable, and Mycroft had been slightly surprised that Sherlock had attached himself to someone who apparently didn't have an angle – didn't want anything from him. Until he met Molly Hooper, he believed the idea of selflessness to be just that – an idea, a fictional, fairy-tale construct. Sherlock Holmes was a man who went out of the way to make himself unlovable, but somehow Molly Hooper found the capacity – and the desire - to love him regardless.

Mycroft had started to wonder about Sherlock's own feelings on the night of the jump. He had it all arranged, had everything in place for his brother's disappearance – but Sherlock had asked him for one night. Mycroft had been reluctant – not only had meticulous plans been made, but he feared what one more night of freedom might do to his brother, and his resolve. That night had been spent at Molly Hooper's house, surveillance watching every angle of the exterior of her home. Mycroft hadn't liked to speculate what went on that night – he didn't think Sherlock would be that stupid, but he knew how emotions could get the better of his brother.

Whatever passed between them, at the point of his leaving Sherlock had been adamant that Mycroft ensure her safety and ensure that she was kept updated. He just wanted her to know he was alive, nothing more, and Mycroft dutifully relayed this repeated message to Molly throughout Sherlock's two-year absence. At first, she had demanded to know more, but eventually that stopped – perhaps it was easier not to know, particularly when the situation might last indefinitely. Likewise, Mycroft told Sherlock very little about Molly – she was alive, safe and well. Sherlock didn't ask for more, and Mycroft would have been reluctant to give it to him.

Of course, Mycroft learned of Dr Hooper's engagement (and initiated the necessary background checks), but knew it wouldn't be prudent to share this with Sherlock, particularly given his uncertainty about his little brother's feelings – he feared the news might cause him to do something rash; either to abandon his mission and return, or to flee further into the darkness, never to return.

Hovering at the periphery of his brother's wedding, Mycroft smiled wryly to himself when he remembered Sherlock's huge discomfort at his role in John Watson's own nuptials. It had been hard not to feel sorry for him, a man so far out of his so-called 'comfort zone' that he may as well have been visiting an alien planet. Not terribly interested in the whole affair, Mycroft had made the point that at least Dr Hooper would be there to keep him company – only to receive Sherlock's gruff response that she had a 'plus one' with her.

Of course, that 'plus one' wasn't on the scene for much longer, a fact that was relayed to Mycroft by one of his ops staff and not by Sherlock himself. With a small measure of shame, he recalled feeling relieved that this change in Dr Hooper's circumstances had not spurred his brother into action – after all, succumbing to sentiment would only end in misery, wouldn't it?

But succumbing to sentiment had been the making of Sherlock Holmes. Mycroft acknowledged that John Watson's friendship had probably saved his brother, helped him to function in society, and that their kinship grounded Sherlock and gave him strength. Mary Watson, too. But when Mycroft saw his brother after Mary Watson's death, his own tenet about the dangers of sentiment felt more relevant than ever – what good were human attachments if they could break you so easily?

Mycroft knew there was only one course of action that night, and that was to arrange to have his brother delivered to the door of Molly Hooper. He had watched through the blacked-out car windows as the door opened and she took Sherlock into her arms and her home. For a moment, Mycroft experienced a flash of fear that there was a possibility he was wrong about everything.

Sherrinford answered that question and then some. Until their showdown with Eurus, Mycroft hadn't come close to understanding the depth of his brother's feelings for Molly Hooper – and he thought perhaps Sherlock hadn't either. He heard himself tell Sherlock he understood how hard it had been for him to make that call to Molly, but why was it hard? Because he was lying to a woman who loved him? Because he was forcing a friend to do something she resolutely did not want to do? It was only when Sherlock set about destroying that coffin with his bare hands that Mycroft realised it was because his brother had been made to face up to and articulate feelings that he fought hard to keep buried – buried to protect both himself and the young woman in tears in her flat.