“No.” Violet rolls her eyes. “I mean, where on her body? It looked like her hand and arm. Is that right?”

“I think so.” I sit on the floor beside the suitcase. “Are you thinking maybe one of these things might have hurt her? When she picked it up?”

There are dozens of objects. One is a silver fork, corrosion-eaten and strange-looking after years in the sea, but not sharp.

“I don’t think any of these things could have drawn blood,” Violet says, pushing them around with her finger. “They’re just funny pebbles, weirdly shaped driftwood, shells and bits. And I think this is an ammonite.”

“What’s that, though?” I say, pointing to an oddly translucent red pebble about the size and shape of a very large egg.

Violet picks it up and walks over to the window. She holds the pebble up. It gathers the morning light and seems to hold it inside itself, glowing in Violet’s palm like a small red sun.

“Cor!” I say.

“It’s pretty,” Violet replies, tossing the pebble in her hand. “But hardly dangerous. I think it’s a big lump of sea glass, that’s all.”

“Nice, though,” I say. “Mrs F has loads of that stuff in her shop. She’ll want it back, I expect. I’ll take it round later.”

“Let’s both go,” says Violet, sweeping the things back into the bucket. “I want to see how she is anyway. And I need to find out more about what we saw yesterday, on the beach.”

Mrs Fossil’s Flotsamporium is in a different part of town from the Eerie Book Dispensary, but the twisting narrow lanes and tall seaside houses look the same. The ground floor is mostly an enormous bay window, filled with jars and bottles. In the glass of the peeling shop door, the word CLOSED is displayed, painted on a piece of driftwood.

I knock anyway.

After a moment, the door opens, but the person who looks out isn’t Mrs Fossil.

“Dr Thalassi!” I say. “We’ve come to see your patient.”

“I cannot advise it,” says the man, his dark brows lowering over his Julius Caesar nose. “Mrs Fossil has had a nasty shock. She needs to rest.”

“Is that Herbie Lemon?” comes Mrs F’s voice, a bit wobbly, from somewhere deep inside the shop. “And his friend Violet? Oh, please let them in, Doc. They were on the beach with me yesterday.”

We enter, and I hear Violet gasp as she takes in the extraordinary interior of the Flotsamporium. The bottles and jars in the window – backlit now by the morning sun – burn and sparkle with translucent pebbles of every imaginable colour. Violet looks down and sees her own body dappled with rainbow light.