She’s been looking forward to scaling the building.

The security of the CAM tower is impenetrable. In drawing up her plans, she set about finding an entry point into the top floor, where even if she sets off alarms, she’ll already be in the right place, able to act immediately.

She’s identified the weakest window on the top floor and designed a path up the side of the building to get there. No belay line or climbing harness -- just some good climbing shoes, a bit of rope to secure herself in place once she reaches the window, and a glass cutter. Plus a spray-bottle of goo (top secret, courtesy of the British government) that will let her stick to glass, gecko-like, once she’s applied it to her gloves and the toes of her shoes.

All very Mission Impossible (though with an admittedly feminine twist; Ethan Hunt probably didn’t put on lipstick and perfume before pulling a similar stunt — but she’d told John she was going out with friends tonight, and she sees no reason not to look and feel her best).

The first five floors are fun -- she feels like Spiderman as she gets the hang of the sticky substance. It’s good stuff, but it’s also a bit terrifying. Hold perfectly still, and it can easily support her weight -- could easily support a dozen more of her, as well. But twist a bit, and it comes right off -- allowing one to imitate a moving gecko, rather than a gecko superglued in place. She focuses on keeping three points of contact with the glass at all times, palms and soles pressed to glass, and she inches her way upward.

It’s slower going than she’d expected; she missed out on the chance to practice on other buildings when she moved the date up, so she didn’t account for some of the difficulties. Keeping her toes still against the glass isn’t easy or natural. She also hasn’t practiced the transition between floors -- the sticky material doesn’t work well on the steel and concrete between the windows, so she has to climb more traditionally there, finding fissures and imperfections to perch on for the few feet between each story.

She worries as she climbs, about John, about Sherlock. The boys have no idea what they’re getting into if Sherlock truly goes after Magnussen. She hopes fervently that they’ll give her enough time to handle him herself, that they’ll stay away from him for at least another week or so. He’s too scary; she doesn’t want Magnussen near John -- nor Sherlock. And besides, Magnussen is hers.

She shakes her head, trying to clear it and focus on the task at hand. But her thoughts keep returning to John and Sherlock, wondering what they are up to, what John was hiding from her. She also uneasily considers her last text to Janine, and the fact that it went unanswered all afternoon and evening -- very unlike Janine. She feels unsettled. Her foot slips a little. Focus. All that will save for later.

By a third of the way up, she’s sweating profusely, and her arms are straining. This exercise involves lots more teeth gritting, face making, and limbs aching than the movies would make it seem. She came up with the plan back before she knew she was pregnant. Since then, she hasn’t been working out as much as she used to. Hasn’t been keeping food down or sleeping as reliably as she once did, either. Ethan Hunt was probably in much better shape when he scaled his skyscraper. She bets he also didn’t have to deal with weirdly sensitive nipples, or with frequent waves of nausea.

She shakes the thought off, keeps going.

Near the midway point, she turns her head to the side and vomits. She learns that experiencing your abdominal muscles convulsing uncontrollably as you hang in the air fifteen stories above the ground, secured by nothing more than some sticky tape that the government is still testing, is a remarkably insecure feeling. She also worries that someone will see her projectile stomach contents and sound the alarm, but she doesn’t spot anyone obviously noticing.

She clings to the side of the building, catching her breath, feeling the nausea subside. It’s an improvement, but she still feels dizzy, uncomfortable where her breasts are pressed against the glass, and angry at her body for being so far from the finely-honed, capable, predictable tool it has always been.

She glances at her watch and swears. This is taking far too long -- nearly three times as long as she’d predicted. She continues.

Two thirds of the way up the building, her arms are shaking, and she’s desperately wishing she’d come up with an alternate plan. So stupid, trying to prove to herself and to Mycroft that she can do everything she could before the pregnancy. The truth is that she can’t. The truth is that even if everything isn’t ruined -- though she still thinks it might be -- she’s going to have to learn to adjust, to think about everything more carefully and approach assignments differently.

Three quarters of the way up, she wishes she’d turned back when she was still only midway. Her arms are jelly; her legs lead.

Between floors 28 and 29, her left foot slips off the concrete. Then her right. Suddenly, she’s falling.

She slips, slides, grabs at the building without finding purchase.

She falls.

Mostly by luck, she manages to slam her flattened palm against the glass, and it catches. Now she is dangling off the building, held up by a single hand.

She realizes that she’d prefer not to die, despite everything. Stupid of her, to make that an option. Gritting her teeth, panting, she carefully places her other hand and her feet firmly against the window. She rests for a moment, then shakily starts up the 27th story for the second time.

She reaches the highest window, finally, finally. She ties herself in place and starts cutting the glass. It’s more difficult than it should be; she’s quivering uncontrollably, lightheaded, and dripping sweat from every pore. (And, as if that weren’t enough, it’s starting to rain.) She’s also aware that she’s arrived here several hours later than she intended, and she’s going to be running into the later shift of Magnussen’s staff, whose habits she’s less familiar with. She should be keeping a careful eye out for movement as she cuts a hole in the glass, but it’s all she can do to just keep going and not fall -- down, asleep; it’s a bad time for falling, all around.

She pushes the circle of glass inward at last, and as it shatters, she unfastens the rope and pulls herself through.

She stumbles to the ground inside the darkened room and kneels, shaking, in a field of glass shards. She pants, closing her eyes briefly as another wave of nausea catches her, then starts to stand -- only to find an arm wrapping around her neck from behind.

Fuck.

The thing about choke holds is that they’re nearly impossible to get out of. She never would have let such a thing happen, usually, she thinks sourly as the arm tightens around her neck, and she’s lifted off the ground. She struggles uselessly, her legs cycling and arms grabbing ineffectually at the thick arm cutting off her air, as she’s carried into the adjacent room.

There’s more space in here, and a bit more light. She can see her captor better, now -- a giant, muscled, bare, pale arm. Fortunately, the arm has poor technique and is only cutting off her air rather than her bloodflow; otherwise, she’d already have passed out. But she is starting to see purple and black dots. Time to come up with a plan.

She can’t reach her gun, which is at her back and pressed up against her assailant. She didn’t bring other weapons in order to stay as light as possible during the climb -- an error she hopes to live to regret. She looks around for a nearby letter opener, anything usable as a weapon. There’s a pen on the desk, but it’s out of reach.

She gives a few feeble kicks and then goes slack. Every muscle in her body wants to keep fighting for air, but she ignores them all. She waits. Her lungs burn. She waits. As her vision telescopes, and there’s a roaring in her ears, her assailant finally loosens his grip.

She shoves her chin down to her chest, getting it between his arm and her neck before his choke hold can tighten once more. Now she is able to twist sideways and duck her head under his arm. Her feet are touching the ground again at last, and she’s writhing free. He starts to huff with surprise, to grab for her, but she’s already behind him and pulling out her gun. She hits the back of his head, very hard, and he crumples to the ground.

She kneels beside him, telling herself she’s disarming him and checking his vitals to see if he’s still a threat. In truth, she’s mostly just panting, reeling, trying to regain her breath and her equilibrium before she has to move again.

She hears a voice from the other room. “Everything okay?”

It’s Janine’s voice. Fuck. Janine was not supposed to be here. Would not have been here if Mary had arrived on schedule. Fuck.

She grabs the pen from the desk and moves toward the doorway that Janine’s voice emanated from, trying to stay out of the line of sight. She flings the pen high, against the far wall, and hears Janine gasp.

Mary rushes into the room while Janine is turned away, looking for the source of the sound. Mary feels a surge of nausea, but there’s no time to hesitate. She stands behind Janine and raises her gun, preparing to hit her very precisely and with minimal force.

She hesitates, just a moment, staring at her best friend.

Janine starts to turn, and her eyes widen as she catches sight of Mary from the corner of her eye. “Wh --” Mary cuts her off, hitting her very precisely and with minimal force. Except that her arms are shaking, and she feels sick, and Janine’s head has moved; she misjudges and hits the back of Janine’s head harder than she intended.

“Shit,” she hisses, crouching over Janine. There’s blood, and the tang of it plus her nausea means that she just narrowly avoids adding the insult of vomit to her friend’s injury. She suppresses the urge and takes Janine’s pulse. She’s okay, but she’s going to have a really nasty headache. “Sorry. Sorry,” she apologizes uselessly.

Janine should be seen by a doctor; Mary debates whether to call 999. Then she shakes herself. No time. Fuck. The worst of her nausea passes, and she turns and runs. She stumbles twice as she mounts the stairs to Magnussen’s private suite.

“Mary Watson,” Magnussen says, looking up in surprise. “Did Janine let you in? I’ll have to have a chat with her about keeping work life and personal life separate.” His words are casual, but a tension underlies them. She can tell he’s flustered by the fact that he doesn’t call her by her birth name, and she feels a flash of triumph. She has worried him, has made him feel unsafe. She tucks the feeling away to savor later.

She takes out her gun and points it at his head. He flinches, just barely. “Always the assassin,” he says softly, cautiously.

She motions him to stand, and she walks toward him slowly, deliberately. “Yes, well,” she says, “That’s the problem, isn’t it? You know about that, so I can’t very well let you go on living. Can I.”

“You wouldn’t kill me,” he says, still speaking casually, but paling. She wouldn’t, of course -- at least not when she has orders to the contrary. But he’s not to know that. He must believe completely that she means it, so that when he defeats her, he will believe her well and truly in his power.

“If you don’t believe I’ll shoot you, you don’t know me very well after all,” she says with a tight smile. She’s close enough now to smell him. He smells like sweat and rancid oil. She swallows, barely, shuddering. Her mouth swims in saliva as she tries to close off her nose. He has no idea how vulnerable she is right now, and she can’t let him know.

He flinches back further from her gun as she draws near. “Y-You don’t want to do this.”

“I can’t let you keep blackmailing me,” she says.

“This w-won’t help,” he warns, eyes wide, fixed on the barrel.

“I think killing you will help a lot of people, actually,” she says calmly, swallowing her gorge yet again and trying to focus on the conversation at hand. “Why don’t you get down on your knees now.”

“Stop! I have a partner,” he tells her as he obeys.

Finally -- the mystery partner. The one who provided the muscle for kidnapping John. This is exactly what they were after, but she controls her expression, looks skeptical. “No,” she scoffs. “You would never trust someone else with your secrets.”

“No, I haven’t. Not yet. But there’s a dead man’s switch.” He smiles triumphantly while also cowering -- a neat trick. He thinks he has her.

She gasps, faking surprise. She and Mycroft have debated whether such a dead man’s switch exists -- to have such insurance without proactively publicizing it to those he blackmails would take both colossal arrogance and unnecessary risk on Magnussen’s part; he has the first in spades, but would he take such a risk? Still, whether it exists hardly matters. The important thing is that they predicted accurately that Magnussen would say there was one with a gun held to his head. They counted on it, as Mary isn’t supposed to shoot him. She’s supposed to threaten him, to elicit information from him, if possible -- but above all else, she’s supposed to surrender. To end with him believing she is fully under his control with no cards left to play. Only then can she effectively begin to feed him governmental misinformation.

Still, she can’t give up too quickly. She would never give in so fast. “I don’t believe you,” she says, shoving the gun closer at his head.

“It’s the truth!” he protests, jerking back.

She lets her voice waver with a touch of uncertainty. “Who? Who is this partner of yours?”

He shakes his head. “Ah, ah. That, I am not telling. Nothing in it for me, is there? But like you, he possesses many hidden talents.”

She lets her eyes widen, and bites her lip. She considers surrendering at this point, but decides to hold off, to elicit more information about his partner. Then she shakes her head. “No,” she says. “I don’t care.”

Magnussen’s eyes go wide at that, and his smirk fades. He thought he had her. He starts to shake, to stutter. “B-- but it-it’s true. He’ll c-come after you.”

“Prove it. I think you’re bluffing. I think I’ll just kill you, and then you will never hurt me or my husband again!”

She hears something faint. Something downstairs? No. Please don’t let anything go wrong now. Not when she’s so close.

“Your h-h-husband, yes. Wh-wh-what would your husband think, eh?” Magnussen stammers on tearfully, unaware. She doesn’t answer, but keeps straining to hear what’s happening. Voices? More of Magnussen’s men? She was sure the backup wouldn’t get here so fast.

“Hhh-h-he... your lovely husband, upright, honorable… so English. What would he say to you now?” Magnussen continues.

She half-listens to his begging as she tries to work out a contingency plan. Depending how many people are on their way, she may have to take Magnussen hostage in order to get out safely. Which will ruin everything. But it may be her best bet for not dying, and she can fix everything again more easily if she’s still alive.

She cocks the gun.

“No, no,” he begs in Danish. He’s nearly sobbing now. “You’re-you’re doing this to protect him from the truth ... but is this protection he would want?”

Then she hears the voice that changes everything.

“Additionally, if you’re going to commit murder, you might consider changing your perfume,” Sherlock says, and just what the fuck is he doing here where is John how long has Sherlock known where is John how long has Sherlock been tracking her what did he tell John how --

“Lady Smallwood,” he finishes.

What? Oh, God. He doesn’t know. (Where is John?) Can she get out of this without Sherlock knowing? She fights a fresh surge of nausea.

She stands frozen (though so exhausted at this point that she can hardly hold the gun steady), running through scenarios.

Kill Magnussen, as Sherlock expects? Give her time to handle Sherlock and John. (Where is John? God, don’t let him be here, don’t let him see her like this.) Untenable -- unforgivable by Mycroft; ruins all her work, everything.

Run away? She could escape, maybe, without Sherlock seeing her face. But she can’t leave Sherlock alone with Magnussen. Sherlock is chaos. Sherlock will destroy everything; he could harm Magnussen -- possibly even kill him, the way he killed members of Moriarty’s network -- or otherwise destroy everything she’s worked so hard for.

Run away and force Sherlock to come with her? It might possibly work. If John’s not here. Magnussen could then tell John about her, but that’s not his way; he’ll likely want to keep that information to himself for future use.

Magnussen straightens a bit. “Sorry. Who?” He sounds more steady now, staring at Sherlock. “That’s … not … Lady Smallwood, Mr. Holmes,” Magnussen says, glancing up at her.

Right. If John’s not here, she can just focus on getting herself and Sherlock safely away, and on minimizing the damage to her work with Magnussen. (Worry later about how to keep Sherlock from telling John. One thing at a time.) But she also needs to appear detached as she does so. Magnussen knowing John is her pressure point has been bad enough. She can hardly cope when John is threatened, as Magnussen is well aware. She can’t afford to let him see how much she’s come to care for Sherlock.

She turns slowly to face Sherlock. She keeps her pistol raised between herself and the biggest source of chaos in the room. She schools her expression to neutral and her voice steady. She asks the most important thing. “Is John with you?” Please let him not be.

Sherlock, staring at her with disbelief, struggles to find his voice. “Hhh-he’s, um…”

“Is John here?”

“Hhh-he’s downstairs.”

Shit. She nods, closing her eyes for a moment and fighting another surge of nausea. There goes her only option.

Why, she thinks angrily. Why couldn’t you just listen to your brother and stay out of it? Or why couldn’t your brother trust you enough to tell you why you should stay out of it? But of course that’s not how the Holmes brothers work.

Magnussen speaks from behind her. “So, what do you do now? Kill us both?”

She glances at him, smiling tightly. Funny that he thinks she’s the main risk to his safety here. Sherlock is, of course, the much bigger threat. Oh, God, how can she save this?

“Mary,” Sherlock says carefully, “whatever he’s got on you, let me help.” He starts to step toward her.

There must be a way out. Stall for time.

“Oh, Sherlock, if you take one more step I swear I will kill you,” she says, trying to sound stone cold and utterly willing.

Sherlock smiles a little and shakes his head. She sees his intent to move toward her before he even starts to move or speak, and she knows she’s out of time. Make a decision now.

As he opens his mouth to deny her statement and calls her Mrs. Watson, everything slows --

-- pulse spiking higher --

-- tang of adrenaline --

-- Oh! Another option.

Don’t be bluffing. Pull the trigger.

Yes.

No!

Yes -- if Sherlock is hurt, John will be distracted -- too distracted to do anything to Magnussen or to come after the mysterious shooter.

There will be more time. More time to escape. More time to think.

Bonus -- apparent kill shot will convince Magnussen that Sherlock is not actually a pressure point. Maybe also that John is not.

(This will hurt John.)

(Very much.)

(As much as discovering all of the lies?)

(Not if Sherlock is not actually in danger.)

How close to apparent kill shot necessary to convince Magnussen? Chest -- much safer than head -- but not too close.

Risky, still.

-- Sherlock lifts his foot to step closer. --

A wave of nausea. Fight it off.

Focus. Last chance to find another solution.

Top priorities, incontrovertible: the target must live. John must be protected. Of lesser importance, but not insignificant: personal escape.

No choice, then.

Or, more accurately: there may be another choice, but it would take a Holmes to find it.

Ironic.

Pulling the trigger, a realization: Mycroft is going to kill me.

The bullet hits Sherlock’s chest

(watch the blood flow --

oh fuck oh fuck that’s closer than close no no must be mistaken --

blurt an apology, “I’m sorry, Sherlock, I truly am,” real emotion breaking through --

“Mary,” he says, sounding shocked, heartbroken),

and he falls backward to the ground.

Oh, Sherlock, oh, oh no. That’s too much blood, too much, and from the wrong spot.

Panic.

Clock Magnussen with the gun to prevent him talking to John, just in case -- hit hard enough? too hard? not sure -- and run.

Reach inside vest for Mycroftphone --

-- dial Mycroft, who’s faster than any police dispatcher --

-- while sprinting to back stairs, slamming door behind --

-- “Ambulance for Sherlock, GSW to chest, mission abort” --

-- hang up.

Vomit.