A/N: Contains spoilers for Sherlock Season 3! Hope you like it and review.

Disclaimer: I do not own Sherlock.

What is she?

It isn't working. This. You're sleeping beside me, holding onto me, and it feels wrong. The image of that small flash drive burning in the fire is in my mind no matter how much I try to erase it. Cold sweat forms on my forehead, my back, and I try to even my breathing, control myself, try not to move so you won't wake up.

It's been hard, facing you. You're an assassin. You were paid to kill. Just how many people did you kill, Mary? I think of so many excuses, reasons why you did what you did, I think about men in the army and how they have no choice, but you weren't in a battlefield. Whatever path you walked, you chose it, and I can't seem to really let this go.

My love for you is still there, only I don't know you anymore. I love the you from before, and she's gone. I keep pretending everything is fine, it's all normal and good, but I don't know for how long I can keep this up. I try anyway. Only I no longer know who I'm doing this for. Is it for me? For you? For us, for our baby? For…Sherlock?

Well, he did shoot a man so we could have a bloody chance as a family. Went to prison. Almost went on a suicide mission – I'll still punch him and Mycroft for hiding this from me. Mary, I can't lose him again. I…I…what am I doing, Mary? Who are you? Why am I here?

What is she?

This question keeps popping up, over and over again on an endless loop, in my mind. The answer is at the tip of my tongue – I can almost taste it, but never truly say it. I'm afraid that if I finally manage to solve this puzzle something will change – something I can't ignore, something that will prevent me from pretending. Yet, I can't escape it. What are you?

Couldn't you just answer me that? What are you, Mary? What are you supposed to be? According to Sherlock, and, well, to you, I'm an adrenaline-junkie. Are you my adrenaline? No. How could you possibly be? You were a break from everything when I met you. From the adrenaline, from the pain…the pain of losing him. You were my anchor, Mary – something solid to hold on to.

What is she?

I wouldn't have been able to go on had I not found you, would I? Couldn't believe the git was actually dead. And I was right! I've forgiven him, you know? But it's the same with him as it is with you – I can't forget. Why do people I love lie to me to protect me? In what universe is that a good thing?

Sometimes I…I feel like something is wrong with my brain, Mary. This not sleeping at night, dreaming about Afghanistan and Sherlock, this can't be good. I'm a doctor, I know it's not good. I can't go through this again. There's not enough sanity in me for it. And there's a kid on the way, for Christ's sake!

So why am I here, Mary? Why am I lying beside you as if nothing happened? It's not just for the baby, not just for us…

What is she?

I don't bloody know!

You're abnormally attracted to dangerous situations and people…

God, you're in my head, aren't you? I must be losing it, Sherlock. Yes, but I wasn't looking for that in her. I wanted to stop. I desperately wanted to go back to normal, or anything close to that, I just wanted to…survive. I was running, I was trying madly to forget you, forget everything that happened, push you to the back of my mind, and in the end I just went right back to you. Danger. Lies. All over again.

What is she?

Why her? Why is she like that too? I just tried to move on, Sherlock. After you were gone, I didn't have it in me to continue…After you were gone, I…I was too. Sherlock lives means John Watson lives, remember? I needed to want to live again. You died and I was just – God, I can feel a fucking knot down my throat, not really something I need right now – here. I was here, and you were never here. Though, you were always in my head – still are, huh, you cheeky bastard?

What is she?

I DON'T KNOW! I don't know, I don't know! The woman I fell in love with. No, the lie I fell in love with. The one who was there for me when you – deep breaths, John, this conversation isn't really happening – the woman who eased the pain, who was there when I needed…I needed you to be alive and she just showed up and managed to–

Oh, I don't know, Sherlock. Truthfully, I have no idea. She was my first real relationship in so long. None of the ones before seemed to matter enough. Most of them hated you, probably because I spent almost all of my spare time with you. There was no consulting detective to ruin my dates with Mary, was there? Perhaps that was it.

No, it wasn't just that. There was something about her, I could never quite place it. Maybe it was danger, the adrenaline, maybe not, but she was cunning, you know? So smart, a great memory, like you pointed out after she…after she shot you. Sometimes I wondered if she had a mind palace, because the way she acted some days just reminded me so much of—

Oh God.

Right here, right now, what is she?

She's –

"You."

I try to yell it, but I've just ran up the stairs to our old flat and apparently I'm too old for this. As I try to catch my breath I briefly wonder whether you're sleep or not. 'Course not, who am I kidding? You rarely sleep.

Awake, as I imagined. Suddenly it's awkward to stare at you, after…you know, realizing. You were laying on the sofa, but in a flash you're in front of me, looking me up and down, checking for bruises, signs of drinking, something to justify my presence here at three in the morning in the middle of the week.

"John? Is everything alright? Is the baby o—"

"She is you," You were about to touch me, but then you freeze. Slowly you stand upright, you're tense. You look almost afraid. "right Sherlock?"

"Yes."

I inhale deeply and walk in, my hands closing into fists, opening, closing, again and again. "How can this be, huh?" My voice sounds funny. It's hoarse and it's barely a whisper. I don't know if I'm about to cry or hyperventilate, doesn't matter either way. "How can I be with her if she is you?"

I'm pacing now, walking from the kitchen to the window and back again. I can't look at you, I can't be here, I can't even be inside my head the way I'm right now. You stand in the middle of the room just looking at me, following me with your multi-coloured eyes. I never paid much attention to them before…or did I?

"You were looking for a substitute, John." All at once, it's like every never ending in my body is hyper-aware of you. Your presence, your stare, your voice. God, your voice.

"Don't say my name right now."

"Sorry." You mumble.

"Don't! Don't apologize!" I stand in front you now, my finger pointed at your face for a moment. I hate how suddenly you are attractive to me. Was all I felt for you lying dormant somewhere in my brain? In my…In my heart?

It's not your fault. How could I've been so blind? I wanted to be, didn't I? I didn't want to know the answer. I was right, this changes everything. I sit on my chair, you follow suit and sit in front of me. You're quiet still, but your hands twitch towards me a bit, as if you wished to reach out to me. I want you to and it scares me.

"I can't do this, Sherlock. I can't." I'm getting choked up, the knot on my throat almost stopping me from speaking. I lean forward, elbows on my knees, hands clawing at my hair. There's so much dust on the floor. You still need me to look after you, don't you? Yet, I simply- "Can't. There's no way."

"John."

"Don't." A shiver. A shiver from just my name. This is not right. What does this mean? What am I supposed to do now? "I can't. Bloody hell, I remember all Harry went through, it is one of the reasons she's a drinker after all. Mum and dad weren't all that supportive and now…"

"You need to sleep." It's four in the morning. An hour? How long did I pace in your living room? Everything's a blur.

"Can't. Need to figure this out."

"John-"

"Sherlock, don't—"

"Listen to me." I am shaking my head, still not looking at you. "Please." My eyes meet yours and all air leaves my lungs. Not good. Not good at all. "Lack of sufficient sleep impairs one's cognitive judgement, attention span and many other brain functions you so desperately need in order to process what you've just realized. Go to sleep."

It sounds like an order, but all of the sudden I'm too tired to argue, "Mary—"

"I'll call her."

"She'll be worried, I should go back." I stand up, wobbling a little. Too little sleep, too much adrenaline, that's what I get. I barely manage to stand up straight before your hand encircles my wrist and stops me. You're so warm.

"You're in no state to go home alone at this hour." I already turned and approached you, but you don't let go. You're scared of losing me. So very scared. Your eyes are wide, your chest is rising and falling so quickly…how did I not notice all of this, Sherlock? "I rarely use my room anyway, you might as well take the bed."

Your bed, sweet Jesus, your bed.

"Sherlock, I should just—"

"Not a request, John."

We have a quick staring contest. You're tall, imposing and I fear our proximity along with all this exchanging of looks. I give in. You release my wrist and I refuse to miss your warmth from such a simple touch. You follow me to your room and this couldn't be more awkward if we tried.

"There are, huh, some clean shirts here, and also some trousers I usually wear to sleep." You begin pulling different kinds of t-shirts from a drawer, haphazardly throwing them on the bed, you do the same with the trousers. "They're not exactly your size, but I suppose they'll do for tonight."

"It's fine." You nod and walk towards the door.

"Well…I'll be right outside if you need me."

"Why would I need you?" I say softly, more to myself, really. You frown and look down, hand on the doorknob, "No, sorry. I didn't mean it like that. It's just that I said that to you once, when…when Irene drugged you and—"

We're not a couple.

Yes, you are.

This time I'm the one who freezes.

"John." I turn to you abruptly, probably looking paler and more scared than before. "Go to sleep."

"Right. Yeah, I should." I answer, staring at the clean cotton shirt I'm holding. "Goodnight, Sherlock." You linger by the door, just observing for a few seconds.

"Goodnight, John." You close the door and I hear your footsteps towards the living room. I take several gulps of air, still panicking.

Oh, God. What now?