Second: Sherlock fell hard for John (on the ground)
Sherlock knows, the moment he lays eyes on John, that he'll have to make sure John will stay alive. He doesn't know why.
He feels a connection, feels that someone is pulling them together, and it takes six months for him to understand what falling feels like.
(That's why he's ready for it when Moriarty tells him to jump.)
He didn't really have friends when he was younger. Sure, there had been Victor, but somehow they had drifted apart. So when John appeared and didn't show any signs of leaving, Sherlock felt like something had clicked inside him.
And it horrified him.
Sherlock watches. He looks, observes, John, when he runs to the body. (Please Mycroft help me make a duplicate he said and Mycroft replied I already have one. Please Molly help me fake my death he said and Molly replied I already have your brother asked me.)
John seems so broken and Sherlock can't look any longer (but he can't really tear his eyes away, because John was the reason he stayed alive and the reason he faked his death).
He mouths I'm so sorry and turns to leave because if he stays, he'll just ruin everything by walking up to John and telling him I'm alive I really am that is just a clonedollsomething that Mycroft made.
At some point Sherlock had realised he didn't like John's girlfriend's and was that jealousy he was feeling? He made a point of being rude to them (which John thought was just his normal behaviour) and most of them left when they realised John wasn't completely theirs.
All the women and their silly ideas that John would want a boring domestic life (John didn't obviously know what he wanted because he still pursued relationships with those women). Sherlock thought that he might have been able to let John go, if he'd found a woman who wasn't boring but complimented John and gave him what he needed.
(Though a part in him was whispering don't lie to yourself you always search the truth why would lies be okay now and he silenced them down.)
Sherlock is alone in a hotel room and staring at John's blog (Mycroft had said he will break but he hadn't wanted to believe) and wondering how John is managing and if he guesses his password, will there be updates that are meant for only John's eyes.
There's only a bed and the laptop and a few pieces of clothing and a gun in the room because he has to travel lightly and use as little money as possible. He misses John but he has to do this to make sure no one threatens John's life anymore because what would I do without my blogger, that's why.
(He never really tries to guess John's password because he doesn't want to know.)
When John decided that it was okay for Sherlock to ignore personal space (mine not others' they might not like it), he took the most of it, trying to be normal. Sometimes he stood behind John (not touching but only barely) reading what the man was writing on the computer, making John jump a little when he realised that Sherlock was there.
Sometimes he touched John's arm, shoulder, neck, when he kept pouring out his deductions and John's breathing stopped. He let go, fearing he had crossed a line, and continued with the deductions, telling John exactly what had happened and how and then leading him to a chase that sometimes was worse than either of them had anticipated and they were panting at some corner, guns aimed at their direction. (Don't shoot him don't I can't manage without him anymore Sherlock's heart was crying but his mouth was shut and brain told the heart shut up shut up shut up.)
Afterwards they collapsed on their beds or sometimes on the sofa and Sherlock's head was in John's lap and John's hand was in Sherlock's hair and Sherlock had to try hard not to purr.
He still keeps tabs on John and sometimes he visits his grave (staying unseen) when John does and when he hears John speak, he lets his heart break a little and recites in his head caring is not an advantage but nothing inside him will believe it.
He has caught most of Moriarty's henchmen by now but he can't, he still has to stay dead because there's still Moran and that's the man he wants to, no, needs to kill.
Because Moran was going to kill John.
At some point Sherlock had realised that falling hurt when there was no possibility for feelings from John (the others must have been blind not to see it and didn't John keep dating a string of women, too?) and when Moriarty began talking about a game, Sherlock understood he would have to fall again.
(Falling's just like flying except there's a more permanent destination Moriarty's voice kept saying in his head and he wondered if that had meant the jump or)
When Sherlock finally reaches Moran, he's without a gun. I will kill you with my bare hands his posture says and his heart agrees and brain.
Moran is surprised because he had thought it was over for him (he's just a sniper, he's paid for shooting people) and he was on a holiday, well deserved, with money he had got Moriarty. He really didn't need to see a ghost come and ruin it all.
Sherlock doesn't quite remember what happens then.
Soon Moran is dead in his own blood and when Sherlock looks into a mirror, he sees his clothes are bloody. He goes through Moran's clothes to find something to wear before leaving to catch the next flight back to London.
Sometimes Sherlock thought he saw something in the way John looked at him or the way he turned away when John caught him looking, but he usually deleted it. Because.
Mycroft could be wrong, couldn't he?
Walking into the bar he's seen John go some time ago, he wonders how it will be. And he's prepared for a punch, for punches. He sits down to John's table and waits for him to notice someone there before
"Hello John."
And there's the familiar glint in John's eyes when his fist connects with Sherlock's jaw and Sherlock grins.
"Let's go home," he suggests and John nods alright and follows Sherlock, who begins whispering the previous year into his ear and John doesn't mind, doesn't mind that he's forgotten personal space, again, with him.
And when John kisses him, his mind spins and he's shocked and deliriously happy and I said so Mycroft's voice says.
(His heart is singing with joy and he knows or hopes the future to be bright.)