On her wedding day, Mary wakes up in her bed alone. She can't remember if it was her idea or John's to spend the night before the wedding in separate beds, but it is a good one, because she opens her eyes to find that she is holding her dagger. It's a small sliver of super strong plastic and mother of pearl disguised as a bookmark that she always keeps in a cheap novel next to her bed. It has come in useful more than once.

She takes a breath, calming herself as she tries to remember her dream. She was the heroine in the Hitchcock movie, Notorious. Alicia was her name. A spy who ends up marrying the man that she is spying on. John had forced on her the tradition of Movie Nights, insisting that she see the famous key scene. Although she had said nothing at the time, something about the movie disturbed her. For days afterward she was reminded of the heroine trapped between her love and her duty.

Betrayal.

Marrying John without telling him who she was is a betrayal.

She takes another breath, forcing herself to put the knife away. Then she lies back remembering… a large house, a sweeping stairway. Black and white images that gain color in her mind until she can see the burgundy of the wine, the blush of red lips. It was romanticized, simplified, much too glamorous to be real, even so, she understands how it must have felt to be Alicia, wondering if love should even matter, working for a country that didn't care if she lived or died.

She remembers what it felt like to be a tool of the state. Someone interchangeable, given harsh orders from people who hadn't cared at all about her. The callous wastefulness... it leaves a bitter taste in her mouth. But that's all in the past. She got out in time.

Now, if she met someone from her past, they would be her enemy. They wouldn't try to blackmail her like CAM is doing. They would kill her, but they would make sure to kill John first. Because the worst betrayal, to them, is having the gall to think that a peaceful escape is possible for one of her kind.

She closes her eyes and sees John in his wedding suit, blood and brains splattered across the floor of the church. She's out of bed in an instant, running for the loo, but she doesn't quite reach the toilet before she vomits all over the floor. Later that morning when John makes her eggs for breakfast she can't eat a bite.

Despite the bad start, Mary's wedding day is truly the most beautiful and blissful days of her life, even with her fear that someone might barge in and shoot them all. The weather is lovely, and all of the planning works out perfectly. What she doesn't expect is how pale Sherlock is, and how close he comes to fainting away during the wedding.

"Don't lock your knees." She whispers to him later as he stands ramrod straight in the reception line. He looks around nervously, eyes darting back to John. They always return to John.

She hadn't been there when they chose the wedding clothes since Sherlock considered visiting his tailor a solemn occasion not to be witnessed by the fairer sex, so she was surprised when she first saw them standing side by side in identical suits. An elderly guest asks which one is the groom, and Janine jokes that perhaps she should have married them both. Mary smiles as she always smiles at Janine's jokes.

They often say that the bride glows at a wedding, but there is no doubt that the groom is the star of this one. John is radiant. Where Sherlock acts stiff and nervous, John seems perfectly at ease. He looks relaxed, and happy. He is indeed the most handsome that Mary has ever seen him. The John Watson that she had first met was a broken man, but in these last few weeks, he's blossomed, and it isn't due to her efforts alone. It was both of them, she and Sherlock together, who had made the happy, confident John who stands here today.

Would he still be smiling if he knew about her? Should she tell him that she knows three ways to kill a man with the wine glass in her hand? Perhaps, if she had confessed to him before the wedding, told him who she was... But now it's too late. How could he see her lies as anything but disloyalty. John is, after all, an exceptionally loyal man.

Sherlock and Mary stand shoulder to shoulder watching him as he strides across the room to greet Major Sholto. She imagines his face darkening as he learns the truth about her, and the wine turns rotten in her mouth. She makes a face.

"I chose this wine, it's bloody awful."

"Yes, but it's definitely him that he talks about?"

John is smiling at his former commander, and Sherlock is jealous. He pouts so adorably that she can't stop herself from teasing him a little. She grabs hold of his arm and squeezes.

"Oh Sherlock, neither of us were the first, you know."

Since Sherlock's return he has been so desperate to regain John's friendship. He has focused on it with laser sights. And one of the problems of focusing, as any sniper knows, is that you are no longer aware of the world around you. She keeps his focus tightly on John so that Sherlock won't see her.

And today that takes no effort at all, because John is perfect. He looks whole and well and happy because both of them are here. They stand united, odd confederates joined in an unspoken alliance to keep the harsh realities of the world at bay for at least one day. To give John Watson this one perfect day, before the world comes crashing in on them again.

Mary can't help but smile though. She has won, because when the party is over and they go their separate ways, John will go with her.

"Stop smiling," Sherlock says.

"It's my wedding day," Mary replies.

After dinner, Sherlock makes an odd and insulting speech which turns into an incredibly tender and touching one. John is moved, but being the repressed former soldier that he is, he doesn't want anyone to know. It is all very sweet. There are times when the world intrudes on their blissful bubble, like when one of the telegrams turns out to be from CAM. A little beam of darkness sent just to ruin her mood. It reads:

Mary,

Lots of love, Poppet.

Oodles of love and heaps of good wishes

from CAM

Wish your family could have seen this.

Her family.

What an awful thing to mention on her wedding day. CAM deserves a slow knifing for that message. Shame she doesn't have time to assassinate him until after the honeymoon. She realizes that she's frowning when John bends over to comfort her. She brushes the thought away and smiles.

Sherlock's odd speech is all about John, so Mary is surprised when he finally mentions her.

"Today you sit between the woman you have made your wife, and the man you have saved. In short, the two people who love you most in all this world. And I know I speak for Mary as well when I say we will never let you down, and we have a lifetime ahead to prove that."

John leans over to her and whispers, "If I try and hug him stop me."

"Certainly not."

John did rise and hug him, leaving the room in tears, and giving Mary time to hide her own emotions. "We will never let him down."

Never?

It wasn't a word that Mary was used to using.

Lifetime?

A lifetime could be as long as decades, or as short as the next breath if one was in the line of fire. But if she took Sherlock's vow as her own, if she decided to never let John down. Could she? She loved John, yes, but would they really have a lifetime to prove it? Magnussen had found her. How many others would? How many times would she have to kill to keep John safe?

Sherlock's speech is long, too long, oddly long.

"Vatican cameos."

"What did he say? What does that mean?"

"Battle stations. Someone's is going to die."

"What?"

John places his hand on hers and then stands alert for any action. Mary looks around, but no one seems to be in immediate threat. Mary had thought that the reception would be boring, but it isn't. Not with the attempted murder and Sherlock's insane speech as he tries to figure out who the murderer is.

Sherlock's speech is the most bizarre piece of theatre that she has ever seen. It ends with Sherlock and John running off without her to solve a murder. Well that isn't going to happen.

Mary finds them lost on the hotel stairs, and she helps them save the Major. John is on fire! He takes care of the Major's wounds, and still has time to twirl her around the dance floor while Sherlock plays for them. After everything, after all that she has been through, it is hard for Mary to believe that this is really her life. If someone had told her that she would be gliding across the floor in a cloud of joy, in a beautiful wedding dress, held in the arms of a good man, a man who she loved, she would have laughed. But it is happening. She stands surrounded by friends. She might actually cry.

Then Sherlock decides to make another speech and she has to stop herself from groaning. Luckily, this one is much shorter. He says, "From now on I will always be there for the three of you."

Three? Sherlock made a mistake.

But then he explains by saying.

"I think that you should take a pregnancy test."

Pregnant?

Oh God!

The sound of music fades away and Mary hears the thump of a body landing on the floor. It is her mother. Gold strands glimpsed through a doorway. Her father walking forward, gun in hand. The colors of the scene fade until they are the black and white of a classic film. A whisp of smoke rises from the muzzle. No wonder the movie had bothered her. It might have been made of her mother's life.

She plasters a smile on her face and laughs at Sherlock's joke. John is overjoyed. They are having a baby.

A baby!

She covers as best she can, pulling John away to dance so she won't have to talk anymore. Her thoughts are racing, and she's finding it oh so hard to smile.

Mr and Mrs Watson. She had only ever imagined them as a couple. When there are three of them, then they will definitely be a family.

She remembers her father, holding her in his arms and petting her hair to calm her. He said, "One thing about family, Poppet, is that you can never leave it. No matter where you are or what you do, you can't get away from it. They're a part of you, and you're part of them. You and your children will always be part of the family, until you die."