Glaucemetis passed through a huge archway in the rocks, and there loomed up before her the high walls of a great cavern: the cavern that was one of the ancient harbours of the old sunken-city of Poseidonides. And on there on the floor was an object that caught her eye at once.

It was a small black box, all broken and battered, and lying on its side. Its lid was open and the contents had fallen out. It was lined with green, silken, seaweed-silk, and in it lay many strange trinkets of shell, and corals, and pearls, and gold, and little smooth white stones - the sea-washed bones of men.

There was a ring of seven green pearls set in a gold mount, and there were many little white shells of pearl, and an iron arrow with a flint point, all green and rusted.

One of the trinkets was a gold and pearl ring; another was a string of pearls and coral beads, and there was a little knife with a pearl handle.

The strangest of the trinkets was an image of a mermaid all in gold and pearl, with a tail of gold and coral, and on her head a shining golden crown, all set with jewels and pearls. Lying near, caught under a rock, was a shell, like a sea-worn pearl. And all around the rock-pooled water, little, shining lights appeared, and then faded, and appeared once more. And through the water, came a slender grey figure.

"What is this?" Glaucemetis muttered aloud. Her voice was rather like the sound the sea makes as it breaks gently over the sand. She bent over the box, puzzled, picking up one of the trinket - a shiny silver shell.

Glaucemetis let out a small shriek, as a cold, slimy tentacle wrapped its way around her tail, making her fall forward onto the shells, trinkets and bones from the black box.