Sherlock ran all the possible scenarios in his head, trying to figure out the best way to stop Moriarty. To save Y/N. Even after all the different scenarios, he could come up with only one option. So he quickly braced Moriarty and put his foot up on the chess table for leverage. Sherlock was about to throw himself and Moriarty off the ledge when the doors opened. Y/N stood in the doorway looking at the scene before locking eyes with Sherlock. They locked eyes and Sherlock hoped that she could read what he was trying to tell her. What might be his last 'I love you'. He memorized her face before he closed his eyes and launched himself and Moriarty off the balcony.
Moriarty began screaming immediately as he and Sherlock held onto each other, but Sherlock was too busy focusing on Y/N's scream from the balcony. The sound was breaking the detective's heart. Eventually, the men let each other go, falling into the stream and mist of the large waterfall. Sherlock allowed himself to fall a bit longer before pulling out Mycroft's private supply of air.
~~~
Sherlock grew more and more concerned upon his arrival back in London. Y/N clearly wasn't doing well. It was physically hurting him to know that he had caused that pain, but he couldn't break the truth to her yet. Sherlock had to make sure that she was truly free.
Sherlock wasn't stupid. He knew that Moriarty would have people go after Y/N, even if he was dead. So he intended on ending every one of them before he would even think about telling Y/N he was alive. Sherlock took each of the sent assassins out, all while watching Y/N fail to protect and take care of herself. It was breaking his heart to see his love so broken because of him.
The mission Sherlock had sent himself on was almost done. There was just one final person he needed to take out: Sebastian Moran. If anyone was going to continue Moriarty's plans and go after Y/N, it would be that man. Sherlock found himself not going too far from Baker Street. He spent most of his time on the roofs of the flats across the street. He kept watch on Y/N through the windows and could keep an eye out on anything suspicious. Sherlock was watching Y/N slip on one of his shirts over her outfit when he sensed someone's presence.
"I wondered how long it would take you to come," Sherlock commented. He looked at Sebastian Moran who stood to the side, leaning on a chimney while smoking and holding his rifle.
"I had some other loose ends to tend to myself first," Sebastian replied. "Figured you were the one taking out the assassins sent Y/N's way. She's clearly not handing everything well."
"I'm sure your concern means the world. I'll be sure to relay that to her."
"Or I could do so myself."
Sherlock whipped out his gun, aiming for Sebastian's forehead. "Not if I have a say."
Sebastian chuckled. "What are you waiting for?"
Sherlock pressed out a fake smile. "Deciding whether or not to end you now or make it painful." He took a step towards Sebastian.
"Y/N clearly mentioned something to you... you know, she did enjoy it, everything I did. Like—"
A shot rang out over Baker Street. Those in the streets looked around confused as Sherlock watched Sebastian Moran drop dead, blood pouring from the bullet wound in his head. Sherlock threw the gun down and looked back at his flat. Y/N hadn't moved from her spot in Sherlock's chair. He yearned to go over and comfort her, but it wasn't time yet.
~~~
Sherlock was hiding outside the flat, listening in through the cracked open window, when John had convinced Y/N to finally get out of the flat to come and watch Gladstone. He knew that that was his time to show her that he was alive. To make her smile again. He instantly went to John's house, hitching a ride on the back of John's carriage once he left Y/N. Sherlock inspected John's house and found the perfect chair to create a new urban camouflage outfit.
He watched, with so much love in his eyes, as Y/N entered John's office and chatted with John and Mary. He stayed put as Y/N wished the couple goodbye and came back into the office. With a careful eye, Sherlock watched Y/N as she went over to John's desk a read the page on the typewriter. She gasped and teased up, making Sherlock want to read what she had just read. So when Y/N walked back out of the office, Sherlock knew it was his chance. He ripped his mask off, warning Gladstone not to do anything, before carefully going over to the desk. He smirked as he read the last paragraph and added a question mark to the 'The End'. Sensing Y/N had come back into the room, he looked up.
"Sherlock?" Y/N gasped, clearly shocked.
"Hello, my love," Sherlock smiled.
"Are you... are you really here?"
"Yes," he took a step closer to her. "I am."
"I... you..."
Y/N took the needed steps to be right in front of Sherlock, staring at him. She put her hand up to his face but did not make contact. Sherlock watched her, not wanting to make any movements so as to not scare her away. Just when he thought Y/N was going to make contact with his cheek in a loving way, she slapped him. His head snapped away with the impact. Y/N huffed before marching away.
"I deserved that," Sherlock moved his jaw around before going after Y/N. "Darling, please, let me explain. There's a simple answer to this."
"Oh, is there?" Y/N spun around. "Cause I mourned you. I was still in mourning up until mere seconds ago! I... you... I watched you throw yourself and my father off a balcony and into a large waterfall!"
"I know, I know," he came up and carefully grabbed Y/N's upper arms. "I should have told you sooner."
"You should have told me that night before you did it."
"It was the only way to stop Moriarty, you have to understand."
Y/N eyes were tearing up. "I still deserved to know."
His large, calloused hands came up to carefully hold her head. "Truly, I did not know the night would end like that. It was the only way."
She bit her lip to try and keep her tears at bay. "I just... I hurt, so much..."
"I know, I know." His thumbs gently rubbed against her cheeks. "And I understand that my apologies will never be enough."
"No they won't but," she pressed a small kiss to his lips, "never stop apologizing, okay?"
He pulled her in for a longer kiss. "I love you, my love."
"I love you too." Sherlock pulled her in, trying to feel her against him as he kissed her passionately. Y/N pulled back slightly. "You still owe me an explanation."
"Well, I had grabbed—"
Y/N cut Sherlock off with a kiss. "Not now. Right now I need you to love me and apologize some more."
"Yes, my love."