Take pity on her, my son, for mermaids are wretched creatures and she is the most wretched of them all. She was not always so wild, so haggard; in the prime of her days she had hair that drank the sun and skin like silver. But the rocks have taken it all, and without her voice she is a dull and hapless shell that breathes the surf and frequents our shores.

Be kind to her, child, for though you build her castles from the sand she fears us more than you can understand. Her eyes are blue with hunger, but she remembers the cruelties of our forefathers and keeps her distance. Men have twisted her sanity and snatched the songs from her throat, and she was never a strong creature to begin with.

She recalls what they did and yet she longs for a touch, a promise, and that makes her all the more pitiful. She watches from afar, in a secret place among the rocks, and though the tide will eat your castles she dares not approach long after you have turned your back. She cannot appreciate the things you bring her, the shells you thread with such concentration and leave half-buried in the sand. They are baubles only, and her fingers have lost all feeling.

It is no use calling to her, brave child, for though she hears she will not listen. It is best to forget, to turn your head and grow strong with the sea. You have lessons to learn, a life to lead, and one day soon she will rise to find your offerings swept into the waves. The wide-eyed child who watched the rocks with such intensity will be no more, and in his place will walk a man with sun-browned shoulders and a faraway gaze. He has a penchant for work and building houses (with wood and nails this time), and though she has no voice to cry she misses your seaside palaces most of all.

But do not turn away from her, sweet lad, for she knows you cannot part with the sea. Dig your cottage on our shore instead and proof the foundations with wind and salt and rock – all the minerals she trusts by touch and instinct. Her yearning will grow stronger than ever – a ripe, weeping flame within a corrupted breast – but you must not fear when she comes in the night to drowse by the window or scratch at the door. She is lost, and her loneliness knows no boundaries.

Perhaps a day will come in your lifetime when you wake to find the sea a stranger, though you have toiled for years to craft an understanding. The change will be subtle and hard to place, and you might stand a long time by the water while the wind whips your graying hair and foam gathers by the rocks. The sun is too bright, you realize, or not bright enough; the reflections in the sea are ghostly and misshapen, void of some former magic. There is no depth to the air, neither salt nor sweetness, and the tide seems sullen and deflated after a mermaid's glory. It is only then that you turn away, weary and slump-shouldered, while your children’s children run and shout and build their own castles from the sand, where the waves might one day harvest her bones.