I sit back in my chair and fold my arms. “That’s not how it works. When I say ‘clues’, I mean labels and name tags. I mean when someone scratches their phone number on the underside of their suitcase. Do you have a phone number scratched on your underside? No? Well then.”

“But I do have this,” says the girl, and she reaches into her ratty pullover and pulls out a folded postcard that she is wearing on a ribbon around her neck. She takes it off and hands it to me.

On one side is a picture of a monkey wearing a top hat. Or is it a chimp? Either way, it’s not your regular monkey or chimp: it has the lower body of a fish. Printed on the back is a series of letters and numbers.

I glance at the girl because this is something I recognize. But I’m not ready to tell her that yet, in case it sets off the whole detective thing again.

“It was in my cot,” says the girl. “When they found me, twelve years ago, in one of the rooms of this hotel. Surely you know something about it, Herbert.”

“Seriously, call me Herbie,” I say, handing the card back. “Only Mr Mollusc calls me Herbert.”

“Who’s Mr Mollusc?”

“He’s the horrible man who will kick you out into the snow when he finds you down here. And me too, probably.”

“Don’t you mean if he finds me?”

“Er, he’s already nearly found you once,” I say. “And thanks to you, my cellar was trashed by a hideous man with a hook for a hand. So I’m sticking with when, thanks.”

She looks crestfallen.

“So you won’t take my case?”

“Case? Case?” I shake my head in disbelief. “The only cases down here have unwashed pants in them. You can stay here tonight. It’s freezing outside …”

She beams.

“… but I don’t take cases, and I don’t see how I can help you.”

“My name is Violet, by the way,” she says, grabbing my hand and waggling it up and down. “Violet Parma. And I just know that if anyone can help me, Herbie, it’s you.”

It’s as if she hasn’t been listening to a word I said! I watch as she slips off her ridiculously flimsy shoes and props them by the fire. Outside, the snow has stopped and ice has bloomed across the window. I want to ask her about Boathook Man. I want to ask her where she’s been all these years. Then I wonder if she’s hungry, this Violet Parma, but by the time I open my mouth to ask, she’s already asleep on a pile of coats.