This is/will lead into a John/Molly multi-chapter fic (that is rather very long). With a sprinkling of Sherlolly friendship and JohnLock bromance. Reichenbach Spoilers and such (although I think we're all past that). I don't really know what else to say. I've been working on this for longer than anything and therefore keeping it to myself, but no more.
Molly Anne Hooper, along with the rest of humanity was unaware that the 'great' Sherlock Holmes was in fact, alive.
Sherlock knew how to cheat death without the knowledge transferring to any 'lesser mortal'; yes, Molly had helped him, but he had never let on what anything had meant, what his final experiment in the gloomily lit labs of St. Bart's was really for.
He had said he needed her, she was the one person with significance in his life that Moriarty, and even himself, had managed to gloss over. Sherlock Holmes needed Molly Hooper for many reasons, not only in that night to help him defeat his own end, but also after the world and her thought him dead.
He needed her to look after the few he would leave behind, to be strong for Mrs Hudson, Lestarde and most of all Doctor John Watson. He needed her to prove him not a fraud once he had been dead for a month… 'that is, of course, only if it comes to that Molly.' He needed her to make sure no person beside himself and Moriarty were allowed onto the roof. He needed her to switch shifts so that she wouldn't be asked to complete his post mortem, 'I may have been informed that I posses no heart, but to let a college… no, a friend, go any further than the identification of my corpse would be more than heartless.'And finally he needed her to believe that his plans had failed and that his fall was the final step he was to take amongst the living.
He had worked in almost solidarity that night, Molly only there, close by, a hand if he required one, a caffeine source when his body cried for the basic life preservers, and in one weak moment a shoulder to cry on (that one shocked them both).