I turn from Jasper, closing in on his inflatable dinghy, and run up the beach toward a long, dry cave.

The cave: the one where Mam and I hid the pearl.

I barely notice another boat at the other end of the beach, pulled up onto the dry sand. There are some small tents too, quivering in the wind, and a larger green canvas tent, exactly the shape and color of the little plastic houses in a game of Monopoly.

The tents must belong to the archaeologists, although there is nobody about. I conclude they have left their tools and tents and returned to the mainland.

I stagger-run some more. The cave is getting closer. I have to stop to throw up, and I sink to my knees, bringing up a belly-load of seawater. I look back at the sea: the rescue boat with Jasper in it is very close to the shore now. I can make out his black beard.

I run some more, and I am at the mouth of the cave.

It stinks—an ancient smell of dry seaweed, salt, and dead seabirds.

It is dark too. Only a short distance into the cave it is already hard to see. I blink my eyes hard, but it does no good; I stumble forward, hitting my bare toes on jutting rocks.

Yet I know exactly where the clay box is. At the very back of the cave, it sort of splits into a fork—one fork is barely an arm’s length deep, and ends in a slope of sandstone. The other is longer: a narrow passage almost as high as I am, and almost as long, that ends in a huge boulder.

The boulder conceals a turn, a bend in the rock that no one could find unless they knew it was there.

Old Paul knew. Mam knew. I know.

I can squeeze most of my body round the big boulder, then I stretch out my left arm, and feel a short, sandy ledge, and then…

Nothing. My breathing quickens as I pat my hand round the ledge, and the rock behind it. Have I knocked it off? It is not there, for sure, and a dreadful fear begins to rise in me.

Then I feel a cold, hard hand grab my other wrist, and I cry out.

I turn to face Jasper.