It was twilight as I approached Hogwarts castle. My cloak fluttered behind me, and my hood obscured my view. No need for me to cause unnecessary fuss. I caught sight of the white tomb that shone through the dusk and took a moment to pay a thought to the man who rested there.

As I approached the door, Hagrid stopped me. He looked much older than I remembered him, but it had been at least five years since I'd seen the groundskeeper.

'Good ter see ya! I really bin missin' ya.'

I threw back the hood of my cloak. 'I've missed you too, Hagrid. It's been far too long.'

'Headmistress is waitin' for ya, John Watson.'

'Thanks, Hagrid.'

That is right. I, John Watson, am a wizard. I went to Hogwarts shortly before Harry Potter did. He was a first year when I was a seventh year. I hardly remember him from Hogwarts, beyond him being yet another terrified little first year in our common room.

But this is not a story about Harry Potter. This is a story about myself, and a wonderful, amazing Muggle that, in his own way, made a difference in a world that he had nothing to do with.

As I walked through the corridors of the castle, I felt at home and completely out of place at the same time. It had been more than a year since I'd last been anywhere magical, and for good reason.

I absentmindedly rubbed my shoulder that was aching as I approached the stone gargoyles outside the head's office.

'Felicia morphiga' I said, and the gargoyles jumped aside. I walked past, sparing a glance for their ugly faces before quickly climbing the stairs. I paused outside the door and took a moment to suppress the old schoolboy nerves that had popped up from being here. As I raised my fist to knock, the door swung open, and I saw Minerva McGonagall sitting at her desk, beckoning me inside.

'John Watson, It has been far too long.'

'Hello, Minerva,' I replied. 'You look lovely as ever.'

'Please, sit down.' She stood and began to make a pot of tea. I crossed the room and sat at the chair in front of her desk.

'Things are so much different now, aren't they?' I commented. 'It was just yesterday I was here with Dumbledore getting in trouble for one thing or another.'

'They are different, aren't they. I hear you're living with a Muggle man now. Not the lady's man I remember from your years here.'

I sighed. Everyone loved to imply that I was gay. Not that it was completely false, but I still got tired of hearing it. Sherlock wasn't interested in that sort of thing, and I accepted that a long time ago.

'He'd just a flatmate.'

Minerva looked at me again, just a little too closely for a little too long before she said, 'I see.'

'Yes, well…' I cleared my throat. Minerva poured a cup of tea and handed it to me before settling back in her seat with her own cup.

'Tell me, John, what have you been about lately?'

'Ah, well. I'm a doctor now. You know, the Muggle version of a Healer. And I go out on a lot of cases with my flatmate.'

'That sounds rather interesting. What kind of work does he do?'

'He's a detective. Calls himself a consulting detective. He's always getting himself into trouble. Usually it's me who's got to pull him out. Our last case he was nearly dragged down in the Thames. And the case before that he nearly got me killed by Chinese smugglers. And for some reason, he has this strange fascination with my scar. He's always asking to see it.'

Minerva cocked an eyebrow at me and regarded me curiously.

'What is it?' I asked. Sometimes she could be quite unnerving.

'And here I'd thought you'd left the Aurors for a quiet life.'

I laughed. 'So did I. But my flatmate's a bit mad, yeah.'

Minerva smiled. 'So it would seem. Are you not concerned he'll-'

'-figure out it's not actually a bullet wound but a leftover from a curse?'

'Well, yes...'

I laughed again. 'He's yet to wonder how the tea makes itself in the morning. I think I'm alright.'

'I do hope so, John, for your sake.'

'I'm sure I'm fine.' I finished off my tea and set my cup on the desk. 'So,' I ventured. ' I assume you invited me up here for some other reason than a visit.'

'Yes, I did.' Minerva sighed. 'I know that you are no longer an Auror, but I'd like you to keep an eye on something for me.'

'What is it?'

'It's one of my students. Her name is Zariel Mondragon. She lives in London, so I immediately thought of you. I've come across some rather disturbing evidence that she might be getting involved with some sort of dark magic. Her teachers have found unfamiliar spells in her belongings, and I've found a few questionable items when I searched her things. I'd really rather not take it to the Ministry yet; if I can, I want to stop it here. She's only sixteen after all.'

I remained silent for a moment. Moving around London wasn't too difficult, but I never knew when Sherlock was going to drag me off for some case. If I needed to, I could always use a concealment charm to get away.

'I'll do it. Like I said, my flatmate's a bit erratic, but I'll do what I can.'

Minerva relaxed a bit. 'Thank you, John. The Hogwarts Express took the students back to London yesterday.'

'Of course, Minerva. Anything for you. You've done so much for me.'

'You would have gotten into the Aurors even if I hadn't said anything. You have passion.'

'Don't forget St. Mungo's,' I added. 'There's no way they would have allowed me to train to be an Auror and a Healer at the same time if you didn't vouch for me.'

'It is not a decision I regret. You are truly impressive, John.'

'Thank you.' I stood and pulled the hood of my cloak over my head. 'Good evening, Minerva. It was a pleasure.'

'Good night, John.'

I walked out of the office pulling the door shut behind me. As I walked through the corridors, I considered what Minerva had told me. The girl had plenty of opportunities to find trouble in London. I should probably start at her house and move on to the seedier magic shops in the area. Knockturn Alley as well. Once I was far enough away from the main gates, I turned on the spot and appeared in 221C a moment later. I looked around the room. I kept all my magical things down here. I hung my cloak next to a pair of robes and left the room, charming the door so that it would only open for me. Thank god Mrs. Hudson was a witch, or I'd have a difficult time hiding all my things.

I hurried up the stairs, making sure my wand was still well concealed in the sleeve holster under my jumper. It really was too bad I couldn't bring Sherlock in on this case. I had been a good Auror, but Sherlock would have been amazing, better than even Harry Potter.