People say I'm generous. They're completely wrong. I've always said I'm a lot of things, and I'll happily provide a list. But if I give someone a gift then, sooner or later, I expect something back.

An example. May, 1986. I'm at the Leaky Cauldron, sitting in a little booth off to the side. I'm waiting for a friend. He's late, which is no real cause for concern, but then something more interesting turns up. This little goblin, with a torn collar, waddles in from the Diagon Alley entrance and struggles up a bar stool. Then he orders himself two pints of ale, and downs one in a single gulp.

Seeing a goblin in a wizard pub is rare enough. There's this unofficial apartheid between wizards and, basically, everyone else. I've never seen the sense in it – it gets in the way of business, and information. Anyway, goblins are usually studious, hard-working, officious little snots. But they're bitter, as well. More bitter than a lemon. And when they get rankled, they tend to go looking for trouble, of one sort or another. The goblin rebellion, if you can call it that, is the best example of this. These days they usually wander into some goblin village to vent their petty wrath. So this little goblin, regretting his lust for ale, was obviously either crazy or stupid. Maybe both. Definitely looking for trouble, at any rate. What he found instead was me.

Which, in some ways, is a lot worse.

"Are you feeling okay?" I asked, all concerned. The goblin looked up, surprised. He looked me up and down, suddenly fuming again, and nodded dismissively.

"It takes a lot of woe to make anyone drink a pint of Cauldron Froth in one go," I observed, not being put off. The goblin made a face, and looked down into the empty tankard next to him.

"It's just the name of the ale," I explained. He grumbled something.

"So what's got you down?"

"Nothing."

"Why don't you come over here and tell me all about it?"

"Don't wanna," he said, and took a swig of the second pint of ale. Clearly a goblin with a loving liver.

"Come on. You look like you could use a drink."

"I've already got-" he began, but I cut in with,

"Barkeep! A pint of ale for the poor… guy."

At the table, he gulped his second pint greedily before turning to look at his third, the one I had bought him. Free, he thought. Ha.

"So what's up?" I asked. "I hate to see anyone with a frown on their face." All sunshine and cheer, indeed. I'm not sure if a goblin's wizened features ever move out of a frown, to be honest.

"Been fired," he muttered.

"Fired? From where?" I asked, in all innocence, looking at his Gringott's uniform.

"The bank," he replied.

"How come? I thought they were really keen on keeping employees, there."

"Why should they be?" muttered the goblin, gulping the ale.

"Because of everything you guys find out, down in the vaults. You know your way around there. I'm sure you know all sorts of useful secrets. Why would they want to go and fire you?"

"Because I called the general manager a lickspittle, and a repugnant wart, and kicked him in the oolygog."

"The oolygog? I'm not well versed in goblin language, friend."

"The oolygog. What's the word? The thing… the head. Yeah, the teeth."

"You kicked him in the teeth?"

"Only slightly."

"Well, you're modest," I said.

"Damn right," he gulped more ale. When he put the tankard down, it was half empty, and he almost missed the table.

"So is it true, what they say?"

"Wassat?" he wiped his mouth on his sleeve.

"That you guys know all kinds of secrets. I've never known a secret before," I said, glumly. Which is, of course, bollocks. I've known enough secrets to make a centaur blush. A few of them about certain centaurs themselves, but that's enough of that.

"Aw, s'a shame," slurred the goblin.

"What ones do you know?" I asked. I was so tempted to actually get out a bit of pencil, and a bit of paper. But I just tried to remember. They flowed out of him as the ale flowed in, as though the secrets had to make room for the booze.

And that's how that happened. He told me a lot of secrets. How to halt the vault-wagons, where the bank was investing these days, how to unlock certain high-security vaults, some of the embarrassing things people kept in their personal lockers, and some of the long-term storage names.

He told me what had been in Volde-man's vault. He'd been penniless at first, but as the extortion, blackmail and indeed tribute accumulated, he'd needed somewhere to store it. The amount of gold stored down there, apparently, would put the Nazi's Switzerland to shame.

Which, interestingly, is how I knew before everyone else that the V-man, He Who Must Not Be Named, was making a very slow recovery. Five years later, I was having a conversation with Lucius Malfoy, his face hidden under a hood as though he could disguise that vile flow of white hair. I happened to mention Nicholas Flamel, only in passing. He mentioned the Philosopher's Stone, and how much he'd like to own it. He told me 'For reasons of his own,' when I asked. I happened to mention Vault 713. And then, weirdly, he happened to drop a lot of money into my palm, and in what I can only assume was shock, I happened to tell him exactly how to reach and unlock that particular vault.

I bought the goblin three or four pints of ale. He gave me, in exchange and without knowing, so very much more.