A/N: Silly, short and light, I'm sure. -csf


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'Hi, John. Please meet John.'

'Sherlock! What did I tell you about animal testing?'

'That you would not stand for cruel mistreatment of animals for the advancement of my own scientific research. You then launched on to a series of breeches to your rule that, as a doctor, you had to concur had greatly advanced medicine and saved more lives, potentially, than it took.' He snapped his eyes up, straight at me. 'Or maybe you said something about mouldy potatoes in the bathtub. It's really a blur, all your nagging.'

'Sherlock...' I warn, lowering my voice to dangerous levels.

'Just kidding, John. I am sufficiently convinced this lab rat – John – will not be harmed in any way. In fact, I've grown quite attached to little John, and I wouldn't dream of having any harm come to him.'

'Little John?' I repeat his words.

'We must make sure to avoid confusion in any way. How awkward would that be for you?'

I glare at my friend, because I know what will soon come; some witty remark about my size. "You are both small, John!" or "No, I meant the one who squeaks the more when he's afraid of something, but I see where you'd be confused, Lestrade!"

I sigh deeply to the critiques I haven't received yet. It's not being insecure, it's being prepared beforehand. As much as you ever can with the unpredictable Sherlock Holmes.

The detective can be relentlessly acerbic. Usually he doesn't mean to hurt anyone's feelings. Lestrade argues Sherlock wouldn't even notice he had hurt someone's feelings, even if he had intended so; but that would be disingenuous and I know better. No, Sherlock still fires witty remarks when he is feeling vulnerable. Like a 5 year old, he can make a mess of his social attempts.

I lean over to the metal cage on the kitchen table. The small, nervous, furry creature comes innocently to the bars separating us – get me outta here, John! he's a mad scientist! – and blinks those reddish eyes at me, as his whole body trembles in fear and trepidation, his whiskers vibrating at warp speed to sense me – please will you save me?

'Alright. You've got a lab rat, Sherlock. Why?'

Sherlock smirks to himself, as if he's just won an invisible battle.

'I'm sending John to the Moon.'

'What?'

Okay, so maybe I did squeak there, but– seriously?

The detective ponders, cold and reasonable:

'I'm building a rocket to send John, the Magnificent Rodent, to the Moon.'

'No, you're not.' I assure my friend.

'Yes, I am.' He says, as nothing out of the ordinary.

'You're really not, mate.' And, amused, I cross my arms in front of me.

'Do not fret, John. Your turn will come, when I'm sure it's safe enough and I can dispense of you for the required length of time.'

Alright. He's succeeded. Not at winning the argument, no. At leaving me speechless.

I watch him lift the cage off the table and carefully carry it on to the living room, full of precautions and in the gentlest of manners. He gets a measuring tape out of his pocket and rolls it out, taking a quick mental note of John's size from the tip of the nose to tip of the tail.

'Did you just give him a piece of cheese out of your dressing gown's pocket?' I challenge at once.

'So what if I had? Rodents like cheese, John. Doesn't take a genius to know that.'

I smile to his back. 'It's kind. You like him.'

'Nonsense, John, I'm not kind! Ask the media!'

'And unsanitary too. Your dressing gown will stink of stale cheese, if it doesn't already! Mrs Hudson will throw it away, you know, in one of her biohazard bags.'

'She will not! I know for a fact that she likes John. She adores him. She might even like you...'

'Very funny', I mutter tiredly. He brings the cage back to the kitchen table, setting it down carefully. Less than attentively he then grabs an electric screwdriver from under the sink. And a blow torch as an afterthought too. 'Sherlock', I start again, more loudly, 'you can't have a pet rat.' Especially not when he contemplates a blowtorch as an essential everyday tool.

'John, I believe you are jealous. Fear not, you are still my favourite. I will warn you, though, that little John is quickly gaining ground.' And with that he rolls the dividing doors from the kitchen to the living room, keeping me out. I stand there, shocked, facing the coloured frosted glass panels.

I shake my head and look over at the new Baker Street resident. I wonder where Sherlock found him. I'm hoping it wasn't lurching in the bins outside. Nah, of course not. Sherlock wouldn't know of the bin's menial existence. Molly? She works in a teaching hospital, after all, but she usually handles the mortuary and this fellow is quite bright eyed. Who, then? Was he found at a crime scene, nibbling at a corpse? Oh, you poor thing, are you in witness protection with Sherlock Holmes?

'Come here, little one', I whisper softly as I open the cage and slip my hand inside to scoop out the scared little creature. He's a feisty fellow, who immediately searches for adventure, trying to wriggle his way out of my grip.

The rat only settles somewhat when he gets a comfortable seat on my jumper's folds and I feed him crumbly bits of cheese. He's so eager he mistakenly bites my fingertip. I hiss and shake my hand to ease the pain.

That's when Sherlock apparently decides to storm back into the kitchen, sliding the glass doors open. One look at the both of us – a glimpse in the case of little John, who terrified by the racket burrows into my jumper – and the detective freezes on the spot.

'What?' I protest. 'Did you come back to tell me he's carrying the Yersinia pestis bacteria responsible for the plague? Because he's just bitten me, I'd like to know with advancement so I can put my affairs in order...'

'Oh, your affairs are perfectly in order now', Sherlock dismisses easily. He ignores my squint as how he would know that, in order to carry on: 'John, John has grown too big to fit the rocket!'

'Wait, you actually built one?'

'Yes, of course. Been working on it for weeks! But John here – unlike you I may add – has grown too big!' he finishes with the most preposterous accusation to the small creature.

'Good', I settle on. 'He wasn't going anyway.'

'Wasn't going?' Sherlock glares at me.

'No.'

'Why would you state such an inaccurate thing?'

'For various reasons, and I'm not a veterinarian, but mostly because John is pregnant and about to have a nice healthy litter of little Johns. He is a she, Sherlock. A pregnant she-rat.'

'Oh.' He blinks, taking in the challenge. 'Should I build a family-size rocket?'

'Not while the young ones are just pups.'

'And to board a rocket with a mischief of rats would take up a lot of space needed for my sub-experiments... Oh, why did I name her John? I should have known I'd be asking for trouble. You are trouble, John! And I mean you, the human!' he huffs, pacing the small kitchen.

I smile softly. I knew I could bring Sherlock round to seeing things my way. I return she-John to the cage and gently close the wire mesh once more.

'Now, seriously... where did you get this lab rat, mate?'

'Crime scene, of course!'

I glance at my bit finger, transferable diseases and all. He smirks as he reads my expression.

'Not to worry, John, she was set free from a lifelong imprisonment as the control subject of a murderous scientist that had a good work-home life separation and used a gun instead of the intriguing array of murder weapons available. John was homeless and most assuredly surplus. Even you must admit it's cruel, John. Giving her life to science and not actually being a part of it?'

'So—' I think it through. 'We've got a new pet?'

Sherlock's eyes narrow as he fixates on the cage. I look on, it's seemingly empty now.

'Did you secure the dodgy lock on that?'

'Nooo...' Only thought of telling me that now?

'Ah.' Sherlock concludes, with a shoulder shrug. 'I'm sure she'll visit.'

Frantic, I try to look under the table and behind the laboratory glassware.

'Mrs Hudson will never forgive you!' I warn.

'Just drop it, John. We all know you did that on purpose. You really need to work on your jealousy, you love being my sole attention focus.'

I chuckle, getting up from squatting on the ground. Really? I think Sherlock just admitted something here. He'll never live this down, if I can help it.

'So what fuel were you planning on using for your rocket?'

We soon fall into a companiable scientific discussion that carries on through the evening, sat by the fireplace.

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