OK, the half-a-face thing is a teensy bit of an exaggeration, but the doc sighs and has the decency to look sheepish anyway. His eyebrows flock from one side of his forehead to the other.

“Don’t forget, you’re the intruders here, Herbie,” he says eventually, slipping the lump of sea glass back into his pocket. “It was not my intention to cause anyone any harm.”

Awkward silence.

Then the doc changes the subject by reaching out and picking up Violet’s book. “Malamander by Captain K,” he says. “One of the more interesting tales associated with the legend. Jenny told me you were dispensed this. I have a copy myself, of course – only mine doesn’t have seaweed stains on it. Have you finished reading it yet?”

Violet says nothing, so I pipe up. “I haven’t read any of it, Doc. Though I’m beginning to think I should.”

“Everyone who lives in Eerie-on-Sea should read this book, Herbie,” says Dr Thalassi, waggling it at me.

“I’ll add it to my to-do list. In the meantime, could you give me the nutshell version, please, Doc? I don’t mind spoilers.”

Dr Thalassi leans back in his chair again. The paraffin lamp hisses softly on his desk, making the shadows dance in the room. “Very well,” he says.

LEVIATHAN

“CAPTAIN K WAS COMMANDER of the warship Leviathan during the later years of Queen Victoria’s reign,” says Dr Thalassi. “He was patrolling the Far North when he discovered a floating island of rock and ice that didn’t appear on any chart. Through his telescope he spied a vast, glittering cavern in the island. Under the glow of the aurora borealis, Captain K ordered a boat to be lowered into the sea, and had himself rowed over, through the wind and snow, to explore.

“As the boat entered the cavern, there came a terrible sound – a screeching, wailing roar that filled the seamen with dread. They wanted to turn back.

“‘Since when have sailors been scared of the wind?’ said Captain K, and he ordered them to row on.

“The cavern led to the heart of the island. There they found a great, stinking mound of seaweed, bones and shipwreck stuff. At the top of the mound was an eerie red glow. Again the men asked to turn back, but again the captain called them cowards. He stepped out onto the seaweed mound himself, and began to climb.”

“Brave,” I say. “But I think he should have listened to his men.”

Dr Thalassi shrugs. “Maybe so. Anyway, when he reached the top of the mound, he found that it wasn’t a mound at all but a gigantic nest. For, resting in a little dip on the summit, Captain K found a large red crystal egg, glowing with its own internal light.”

“How can it be an egg if it’s made of crystal?” I say.