“Oh no, we need to sleep.” I chuck my cap into the corner and flop down in my chair. “I’ve had more than enough of today, thanks. Let’s see how it all looks tomorrow.”

“OK then,” says Violet, more meekly than I was expecting. “Sleep well, Herbie. And maybe barricade the window, just in case.”

“Why on earth should I do that?” I reply, frowning, because that’s a funny thing to say.

“Well, if what we learned today about the malamander and its egg is true –” Violet smiles strangely, heading towards her bed of coats – “we might get a visitor in the night.”

“Wait,” I say, sitting up. “What have you done?”

“Me?”

“Yes, you! Why do you look so pleased with yourself?”

“I’m just saying we should be careful, that’s all,” she says, and that’s when I notice that she’s fiddling with something in her coat pocket. An image of Violet holding the doc’s dressing gown while we fixed the window flashes into my head, and I gasp.

“You didn’t!”

“I did.” Violet grins, and she pulls out her hand. The egg-shaped stone that Mrs Fossil found on the beach, and which the doctor placed on his desk as he told us the fantastic, tragic story of Captain K, gleams a brilliant ruby-red in her palm.

MR MOLLUSC

“IT’S F-TILL F-TEALING,” I say to Vi the next morning, as I struggle to get my teeth through my very stale breakfast. “Whateffer else you want to call it.”

“Is it really stealing, though?” says Vi, turning the egg-shaped pebble in her hand. “Two days ago, it was just lying on the beach with no owner at all.”

“A lot has happened in those two days, Vi.”

“I know. But Herbie,” Vi says, holding her prize up to the light, “what if this is a real malamander egg?”

“It’s too small,” I snort. “Besides, the malamander chased Captain K across the Atlantic to get its egg back, and wrecked a battleship doing it. Do you really think it would just leave its egg lying about on a beach? Or allow Dr Thalassi to wander about with it in his dressing-gown pocket?”

“No, but…”

“Vi,” I say, giving her one of my most discouraging looks, “what you have there is just a lump of sea glass. A stolen lump, at that. I’m not really sure why you took it.”

Vi glares back at me, then slips the red pebble back into her pocket. “Because,” she says, “whether it’s real or not, Dr Thalassi was using it last night to attract the malamander. And I don’t think that’s something anyone should be doing, do you?”

“Maybe not, but I’m expecting the doc to come hammering on my cubbyhole any moment now, demanding it back.”