Mrs F grimaces, and begins to look exhausted. “I really don’t know what I saw, my dears. And that’s the truth of it.”

“There could be a plain and everyday explanation for it all, I suppose,” says Vi. But she doesn’t sound too sure. She glances again at the door through which Dr Thalassi just left.

“Is sea glass valuable?” she adds, turning back to Mrs F. “I mean, more valuable than a genuine dinosaur bone?”

“Oh, don’t mind old Thalassi,” says Mrs Fossil, managing a weak smile. “He’d never admit it, but his museum and my shop are more or less the same thing. He’ll have that old lump of red glass on a pedestal by the end of the day. With a fancy label on it, no doubt. You should go along there and see for yourself.”

We leave Mrs Fossil to her shop and her bandages and head back out into the narrow street. It’s midday, and almost sunny, but there’s still a hard nip in the air, and I want to get back to my cubbyhole. Violet, however, isn’t having any of it.

“I won’t find answers there,” she says. “I think we need to go back to the beach.”

“You’re not scared?” I say. “After yesterday?”

“There’s no mist today,” says Vi. “Why, are you scared?”

“Of course not.” I straighten my cap nervously. “Not a bit.”

“Then let’s get down there,” says Vi, pulling her coat close around her and leading the way.

“I was surprised you asked so many questions about the legend,” I say, running to keep up. “Back in Mrs Fossil’s shop. I thought you were reading about it in the book the mermonkey gave you.”

“Herbie,” says Vi, coming to a halt, “have you ever read that book?”

“Um,” I say, fiddling with my buttons, “not in so many words…”

“So you haven’t read the description of the magic egg?” says Vi. “The malamander egg that can grant wishes?”

“Er…”

“So you don’t actually know what it looks like?”

“Does it…?” I squint, scratching my head beneath my cap. “Does it look like an egg?”

Violet is unimpressed. She turns and marches off towards the beach with me flapping along behind.

We come out through an old stone archway onto the sea wall, which in this part of town is actually fortified ramparts. Ahead of us the beach stretches away for miles, the tide low and the sea only a distant murmur. Directly below us are the spindly tall fishermen’s sheds – black-painted, with seagull-dropping roofs. Reaching up between them are the spikes of stone that jut from the sand like giant teeth, giving them their name: Maw Rocks.

Violet leans out over the wall, and takes a deep breath of freezing sea air. Then she turns to me.