Her name is Alice Monahans. She cleans rooms on the floor below Magnussen's office. Mary chooses her, not just for the location of her job, which is important, but also because of her appearance. Her hair is dark brown, tied in a tight bun at her neck. She wears a long brown coat which sways back and forth as she shuffles, her eyes perpetually downcast. The swish of her coat and her small, distinctive steps are so recognizable that anyone who knows her would swear that she is the one walking down the hallway when they replay this scene later on the monitor.

Alice is steady and predictable. Mary watched her methodical habits as she was cleaning toilets at a nearby hotel. A job she does in the afternoons before coming here to work the evening shift. If they respect the do not disturb sign placed on the door, then Alice should sleep till morning due to a generous dose of sedative in her coffee.

Wearing a brown wig and pointing her face at the floor, Mary shuffles down the hall. The bag, the coat, the shoes, the white collared shirt were easy enough to find at the cheaper priced clothing stores. She'd scoped the room out by flirting with the man who filled the drinks machine, so she knows exactly where Alice's locker is. Mary hides her face behind the locker door when a man in a blue jumpsuit walks into the room.

"Oh hello, Alice. You're early," he says smiling at her as he takes some gloves from a drawer.

She nods, and waits for him to leave the room. Once she is alone, she walks over to the closet and pulls out a cleaning cart. She stashes her equipment in the waste bin and covers it with her coat before pushing the cart out of the room and down the hall to the freight elevators.

The floor below Magnussen's houses a number of offices, most of which close at five. She pushes the cart down the hallway stopping at the corner and bending over as she pushes the button which switches the feed on the surveillance cameras. She'd recorded the camera feed three days ago. It shows Alice moving from room to room, dumping the waste paper and recyclables as she cleans each office. Now she plays it back. A tiny drive sending the signal back to the security office. She looks at her watch and computes how long she has till the feed shows Alice standing here again.

She walks into the corner office and closes the door behind her. Then she pulls off the ugly shirt and trousers revealing a black catsuit. She shoves the clothes into the bin and puts on a cap. Then she pulls out her gun and straps it to her leg before climbing on the desk, opening a panel in the ceiling, and pulling herself up. She goes through the crawlspace until she reaches a service room whose door is always kept locked. She lowers herself and drops down wincing a bit as she feels a pang in her gut. She presses against her abdomen. A few more weeks and she won't be able to do the climbing anymore.

There is a metal ladder on the edge of the room that goes up to the floor above. She climbs it, coming out in a bare white room next to the service elevator. She walks across to the white doors on the other side of the room and peeks through the crack.

Janine is sitting at a sleek black desk a few feet away. There is no way to enter without being seen, so Mary squats down and waits. A man, obviously security, leans over Janine's desk. She rises to her feet and frowns. He knocks a pen off of her desk and she bends over to pick it up. He grabs her buttocks, and she rises pulling away from him and glaring. He laughs and spits out a crude comment before walking away. Janine shoves the pen in a drawer, and sits back down again.

She hears Magnussen's syrupy voice call out then. Mary tries to catch a glimpse of him. She hears two sets of footsteps climbing stairs, then she looks at her watch. After several minutes, Janine finally rises from her desk, but before Mary can fully open the door, there is a beep and Janine returns. She touches a key and talks to someone on the intercom. While she is distracted, Mary slowly opens the door and enters the room. She crouches behind a divider listening as Janine makes a surprised noise. Mary stills, thinking at first that she has been spotted, but she realizes that it is something else by the tone of Janine's voice. She glances at the window, a wall of glass looking out on the city, and sees Janine's reflection walking toward the elevator. That's when Mary strikes, picking up a stainless steel martini mixer and bashing her on the back of the head. She falls to the floor with a satisfying thud. 'That's what she gets for never returning my favorite bracelet.'

The sound has attracted the guard who comes clomping down the stairs to see what is happening. She shoots, rushing past him and up the stairs before the body has a chance to hit the ground. Magnussen is alone. She walks up to him and pulls out her gun. He raises his hands glancing back at the door for help that will never come.

"CAM?" she says aiming at his head.

"Who are you? I know I have seen your face somewhere... recently... on a recording. Ah! Mrs Watson."

"Tell me, how did you find out about me?"

"I acquire information. That is what I do."

"But who told you?"

"If your husband were to find out that you..."

"I can make this hurt. I'm a nurse, I know how to cause pain. Tell me what you have on me."

"It's in the drawer."

"Get it."

Magnussen goes to his desk and pulls open a drawer. His right hand slides across the bottom of the desk.

"If you push that button, I'll kill you now."

Magnussen's right hand stops moving. His left hand carefully reaches into the drawer and pulls out a thumb drive. He walks over, and holds it out to her.

"On the floor. Slide it over."

Magnussen kneels on the ground, places the silver drive on the floor, and pushes it. Mary squats down, gun firmly pointed at him as she snatches up the drive. She glimpses the letters A.G.R.A. before she places it in her pocket.

Magnussen begs. "Coming here. What would your husband think? He...your lovely husband. He's honorable. What would he say to you now?"

Mary cocks her gun. How dare he threaten her at her own wedding and then try to use John save himself. Oh, she will enjoy this.

"No, no, no!" He blubbers covering his head with his arms "You're doing this to protect him from the truth? What is this obsession with honesty?"

"Additionally if you're going to commit murder, you might consider changing your perfume, Lady Smallwood."

Mary freezes. 'Sherlock?' It can't be. She had talked to him earlier that day. He had asked if he could take John out for a case, and she said 'Yes, and give him dinner too' which had led to a humorous discussion of how much weight John had gained since the wedding. There was no way that his case could be….

Sherlock with ratty hair wearing old clothes smiling at his phone as he cried, "Excellent news, the best. There's every chance that my drug habit might hit the newspapers."

'Newspapers? Magnussen's Newspapers? SHIT!'

"Sorry, Who?" Magnussen said. "That's not Lady Smallwood, Mr Holmes."

Sherlock hadn't seen her face yet. He thought she was someone else, Lady Smallwood. If she could leave without him seeing her face...but Magnussen would tell...was about to tell him who she was. This was unfortunate. If she killed him now, she wouldn't find out who gave him the information, and she needed to know. She had to know who the other enemy was. Sherlock! Why was he here anyway? He was supposed to be with John. 'John?'

Mary turned toward Sherlock and pointed her gun at him. Fear for John totally banishing the joy she should feel at his surprise. If John was found near Magnussen's dead body, he'd be jailed. How dare Sherlock bring him here! Unless….

"Is John with you?" she said, her voice a bit shaky.

Sherlock was worse. His voice shuddered as he stammered out a reply, "He's um..."

"Is John here?"

"He's downstairs."

Mary nodded. 'Right, brilliant. So I can't kill Magnussen.'

Magnussen took that moment to annoy her by saying… "So, what do you do now? Kill us both?" Magnussen was a snake, but he would never spill a secret that he could sell later. He wasn't a problem now, but Sherlock... Sherlock was annoyingly honest. He would tell John what she was.

"Mary, whatever he's got on you, let me help." Sherlock said as he took a step forward.

She sighed. "Oh Sherlock, if you take one more step I swear I will kill you."

"No, Mrs Watson, you won't." He took a step. She raised the gun and aimed at his head.

Mrs Watson.

He had called her Mrs Watson, not Mary. Both he and Magnussen knew her one weakness. The reason why she was here in the first place. John, who might even now be on the stairs. She had no time to wait. She had to leave, and Sherlock...he had to die.

The tombstone. John's eyes. The way he used to talk, so hesitant. What a transformation he had made since Sherlock's return. He was a completely different man now. Before, he seemed only half alive. What would he be like when he saw Sherlock's dead body? He would fall to the ground, certainly. Would he even bother to get up again?

But Sherlock would tell! John would know what she was, and he wouldn't love her anymore! Would he stay even a day, even an hour once he found out? His clothes were already packed. He was just waiting for an excuse to leave her. Because of Sherlock.

All those days and nights she had thrown them together, to keep them distracted. And then John had called out his name. If Sherlock was dead, John would be lost again to grief. If he was alive, Sherlock would take him from her. Then again, if he was dying….

John is a doctor, he will try his best to save him...and when he finds out that it is too late, she will be there to help him through it. He will grieve, but they've been through that before, and once the baby is born…

Mary aims and shoots. "I'm sorry, Sherlock. I truly am."

"Mary?" he says tottering back and forth before falling dramatically to the ground.

She points the gun at Magnussen, wondering if she should just kill him anyway, but she hits him instead knocking him unconscious before going to the desk and pushing the button on the phone that calls for emergency assistance. He'd caused more than one heart attack to occur in his office before.

Mary walked out of the door and hid around a blind corner as John strode up the stairs. She let him pass, and then she rushed down and back the way that she had come. She was quick, but not quick enough to escape the sound of John calling out…"Sherlock! Sherlock!"

She let the door slam shut behind her.