Back in the past Moriarty aimed his gun.
"Goodbye Mr Holmes"
The TARDIS burst into the room, with a large crackle of blue light. John ignored the unusual arrival of the spaceship and charged Moriarty. Sherlock literally flew out of the TARDIS and barrelled into Molly, just as Moriarty pulled the trigger. The bullet hit future-Sherlock in the chest. He didn't have to be a Doctor to know it was fatal
"Sherlock? What?" Molly stammered. She kept glancing between him and past-Sherlock, which had the gun trained on Moriarty, who suddenly fizzed and disappeared. Future-Sherlock sighed in relief. Molly was safe. When he next opened his eyes past-Sherlock was coming over. John looked weary.
"Oh God!" he exclaimed "now there's two of you!" then he saw the wound and his eyes widened "you're hurt!"
"No. stop, don't fuss" future- Sherlock was fading. Not dying, just simply not existing. He looked his younger self in the eye
"You understand" it wasn't a question it was a statement.
"Yes, you are obviously from the future, the way you threw yourself at Molly, suggests an accident that caused her death. The fact that it was this point in time, as well as the fact that you are wearing the same clothes as me suggests that it is the recent future. Does this mean I die here?"
"No" replied future-Sherlock "I will not die, I am ceasing to be. But the fact that Molly is alive will create a paradox. If I tune myself into the TARDIS, which is what I have been doing for the past few days, I will bear the brunt of the temporal explosion and keep the paradox stable"
"You're… you're sacrificing yourself" choked Molly.
"If you want to put it like that. I will have never existed. You won't remember this. The bullet will have missed and you will be alive. That's all I want now. You to be safe"
"But Sherlock-"
" Don't. Just get into the TARDIS" The TARDIS had materialised behind them, the past-TARDIS. The TARDIS that Sherlock had come in had already ceased to be.
"listen to me Molly." Called out future-Sherlock as she turned. She walked back towards him and knelt next to him.
He whispered "I will always and unconditionally love you my Molly Hooper-Holmes"
Her eyes widened, but before she could say anything, John had dragged her into the TARDIS.
Past-Sherlock bent down "I marry Molly Hooper?"
"Not anymore. The paradox will cancel it out. But make sure you do. She's too good to lose"
"I will"
"Now go. And remember I'm giving her the days. The days with you. The days to come. I'm giving you my days. Use them well."
Past-Sherlock smirked "do I really turn into a sentimental idiot?"
"Shut up! Go!"
Future-Sherlock watched as his past self-ran into the TARDIS. He closed his eyes as she dematerialized and retreated to his mind palace. To the room of his memories. Running with John, experimenting in the lab with Molly. He was content, as the white light engulfed him and he ceased to be.
Did you really think I would kill off Molly!? Nah I would never do that! Virtual hugs and cookies to anyone who can spot the quotes that I have used in this and what episode they are from! Hint: Amy and Rory. I will be finishing up this fanfic very soon (I've only planned 25 chapters) so I will try to end it on a more or less happy note. But that might change depending on reviews!