Summary: An attempt to untangle what happened that night in Magnussen's office, and why. Huge spoilers for "His Last Vow." If you don't know what the title means, you probably shouldn't read it. :P
A.G.R.A.
by kaineikarra
"Sherlock, if you take one more step, I swear, I will kill you."
He takes a small step forward, his face soft and certain. "No, Mrs. Watson. You won't."
Time seems to slow. She sees the future splintering out into a thousand possibilities, a thousand outcomes all pivoting on this one moment, this one decision.
She does nothing. Sherlock takes the gun, John finds her here, John leaves her.
She swings the gun at Sherlock's head, trying to knock him out. But he's too tall, too fast—he catches her arm, takes the gun. John finds her here, John leaves her.
She turns and runs, fleeing back the way she came. Sherlock's long strides catch up to her in seconds. John finds her here, John leaves her.
She shoots Sherlock in the knee, the shoulder, somewhere that will stop him but not seriously injure him. She sees him staggering back and falling to the floor, shock and betrayal in his eyes, as she runs from the room and vanishes into the safety of the night. Then John comes, finds Sherlock, and Sherlock tells him who shot him. John leaves her.
It's been five years since she's held a gun in her hands, but the old training snaps back into place in a heartbeat and she knows what needs to be done—the only solution, the only way out.
One shot in the head for Sherlock, one for Magnussen, then out and away before John can discover her. John will never know, never suspect her for an instant.
But Sherlock will be dead.
She spent years dehumanizing people—changing them into animals, villains, cardboard cutouts that she destroyed with casual efficiency. Once they were on the other side of her gun, they weren't real people anymore. They were just targets on a shooting range, today's job to be taken care of before heading home for a shower and a quick dinner. They weren't human beings.
They weren't friends.
They didn't compose beautiful songs for her on the violin, or fold serviettes into swans and opera houses, or gaze up at her with trusting, open blue eyes that saw everything so clearly but somehow couldn't see the horrible secret she was hiding.
They weren't her husband's best friend, the one he'd spent the last two years missing and grieving over. Nightmares every night for months, John told her—always standing there on the sidewalk watching Sherlock fall, trying to run forward and catch him, save him, but never able to get there in time. Watching him die over and over again, waking up screaming his name.
How will John feel, coming up here and finding Sherlock dead on the floor?
It will kill him. It will destroy him, and even if he'll never know that she did it, he'll never be the same again.
"No, Mrs. Watson. You won't."
Mrs. Watson. She's Mrs. Watson now. Not A.G.R.A. Not a ruthless hired gun. It's been five years since she started her life as Mary Morstan, and they've been the best five years of her life. Being a nurse, healing people instead of killing them, evening the score just a little. Making friends, connecting with people, and being just a normal woman with a loving husband and a nice little house and a framed picture from her wedding day on the mantel.
That's who she is now, and the truth is that Sherlock is right: Mrs. Watson would never, ever shoot her husband's best friend.
But if John finds out about her past, that will be the end of Mrs. Watson. And that will destroy John, too.
Time lurches back to normal speed. Sherlock is moving towards her and she knows that in half a second, he's going to grab the gun and everything will be over, her relationship with John and the woman she's become and this beautiful life they've built together.
So, it's a choice, then. Destroy John with the loss of Sherlock, or destroy him with the betrayal and loss of his wife.
The gun shifts down, aims, and fires, and just like that, she's made her choice.
Sherlock goes still, a look of disbelief and confusion on his face. Blood flows from the wound in his chest, dark and unforgiving against the white of his shirt.
"Mary?"
She swallows, pushing away the sick, guilty self-hatred curling in her stomach. "I'm sorry, Sherlock. I truly am."
He falls onto his back on the floor, bleeding and dying dying because of her, dear Sherlock, loyal Sherlock, trusting Sherlock, and after she's knocked out Magnussen, she grabs her phone with surprisingly steady fingers and calls for an ambulance.
And then she leaves. She doesn't look back, never looks back, but Sherlock's face is vivid and searing in her memory, and despite a lifetime of putting bullets into people, for the first time she feels like she's done something really, truly horrible.
It's very likely that Sherlock will die. But she's given him a chance, small though it is, to survive, and while it's far too cruel an act for Mary Watson, it's the kindest A.G.R.A. has ever been to someone who got in her way.
When she gets home, she sits on the couch holding the framed photo of her, John, and Sherlock at the wedding, and waits for John's phone call.
A.G.R.A. never cried for her victims, but Mary Watson does, tears streaming silently down her cheeks. They cling to her chin and then drip down onto an image of three happy people, three friends, who may never be happy again.
After a while, she lays the picture face-down on the coffee table and sits there in the dark, arms folded, waiting for the phone to ring. Waiting for John to tell her if she's killed a man tonight or not.
And somewhere deep inside her mind, the cold mirror face of A.G.R.A. smirks at her, laughing at how weak and soft she's become.
And she has become soft. She knows that. But soft is not the same as weak, and that's something A.G.R.A. never understood.
But Mary understands, and she doesn't regret that softness. Her regrets are of bullets and blood and blank, staring faces.
And of Sherlock Holmes, crumpling to the floor with her bullet in his chest.
When the phone rings and John's shaking voice tells her Sherlock's been shot, she doesn't have to pretend to be upset. She grabs her bag, puts on her coat, and spends a second examining herself in the hallway mirror. Mary Watson's kind, tired face gazes back at her, but if she looks closely, she can see a glint of A.G.R.A. deep in the blue of her eyes.
A.G.R.A. will always be there, watching and laughing. Waiting.
But for now, she's Mary Watson, and she has to go to the hospital and be there for her husband. If Sherlock is dead, she'll deal with that.
And if he's alive, she'll deal with that, too.