Molly was at the morgue, humming to herself as she cleaned up and prepared to get home.
She was almost done, just taking off the latex gloves to reveal the shiny engagement ring from Sherlock.
There was a knock at the door, a pause, and the door swung open.
She looked up, surprised when John, not Sherlock in.
"Hell John!" She said, smiling at him.
"Hello. I know yours and Sherlock's wedding is coming up, and I just wrote in this. Don't let Sherlock see, though." He smiled a bit, handing her the standard sized envelope that he had pulled from his jacket pocket.
She was surprised. "Um, okay, thank you," she was actually a bit nervous to see what was inside.
"It's nothing bad," he reassured her.
Once comfortable that night in what used to be Johns room, (she had told Sherlock that she needed some time alone, but not to worry) she sat down and opened the envelope.
Molly,
I'm writing you because, in two days, you are going to wed the one of the two people whom I love the most in the world. I am not about to dissuade you, or confess secret feelings for him, but I have some advice seeing that you will be taking on the role of the person who looks after him on a day to day basis. He needs it.
As I'm sure you've seen before, he can be quite cruel, demanding, rude, narcissistic, and the list goes on and on. Both you and I have been prey to his lashing out many times. I'm sure you also know that he isn't trying to be that way (most of the time, anyways). While most people automatically know that it's not okay to do things like call a mass murder "neat" or to get excited over a serial killer, Sherlock doesn't realize that. Again, I'm sure you know all of this by now, but I felt the need to write this. He is sometimes the greatest mind seemingly ever, but you must also sometimes treat him as a small child whom you must explain elementary things to. Always remember that through all of his cruelty, and when it seems as if he despises you, he is madly in love with you. I've seen it in his eyes for years.
Sherlock was possible the worst roommate ever. He never cleans up, just makes messes. He never helps out. He never does any shopping. I was also never bored, so I guess that's something.
I'm sure you know that he is a reformed drug addict. When he's bored, he resorts to self medicating. Force him to take a case when he's pouting for a long period of time because that is what will keep him clean.
All of this said, I must also stress how amazing he truly is. He cares deeply, even though he can't express it. He's smart, actually funny after you get over his rudeness. Interesting, and eccentric. Truly an amazing person to be around.
You deserve each other. Molly, you are perfect for him. You're smart, and will be blue to keep up as well as anyone can with him. More importantly you're kind and patient. Be the person he can count on, and I know you will, because he needs one. I know that you'll always care for him, even on his worst days, and unconditional love is the only way anyone can love him.
He will love you, too. He does, actually. He does not live widely, but deeply, and when he loves he gives his heart and soul, even at his darkest hours.
As Sherlock said to Mary when I got married, you deserve him, and that is the highest compliment I can give.
Best, John.
She wiped a tear from her cheek. She loved that man with all of her heart, and the letter was so accurate and heartfelt.
She snuck into their room to put it into the drawer that was off limits to Sherlock, then headed back into the kitchen where Sherlock was.
"Letter from John, I'm not supposed to read it, probably about me." Sherlock said without looking up from his experiment.
"How-"
Now he looked up and actually smiled at her. "I won't read it."
Swiftly, he moved across the room to stand in front of her and kiss her forehead. She closed her eyes and felt the light touch and relived the words about Sherlock, knowing that they were all true and she loved him for every quirk and flaw because they made him Sherlock.