Sherlock Holmes is an empty shell.
The gunshot wound was nothing compared to other horrors he had faced.
So why in the hell couldn't he remember the past few years?
He remembers working on cases, remembers his drug habits, remembers mousy Molly Hooper.
So just why can't he remember John Watson?
He tries to enter his mind palace, to piece something together.
But he can't. All he finds is a room full of fragments, with no real memories to be found.
How do you forget your best friend?
Molly Hooper sits by his side and tells him of all the great things he has done over the years.
His heart stutters a little when she grabs his hand too tightly, when she fights the tears in her eyes.
He doesn't understand why Molly Hooper is being so nice to him. He only recalls being rude to her, and flirting to get his way.
But she stays every day, even when John can't. She has hope, even when John doesn't.
And one day when Molly Hooper has fallen asleep holding his hand, something in his mind palace snaps. The torn up pieces of his memories slowly drift together like a puzzle.
The memories don't come back in any order or come back all at once.
He remembers small bits at a time.
He remembers John Watson, remembers Moriarty, remembers a not-so-mousy Molly Hooper.
And when it all fits back together, he is the one to grab Molly's hand.
He is the one to pull her to him and kiss her forehead.
He finds that she fits against him like a missing piece, and he finally feels whole.
She had hope, and he is no longer a shell of a man.
His memories are whole.
He is whole.