Alice’s official line on how she got involved in Eva’s work was the islands and their epics. But in truth there was another, deeper, more mysterious connection, which drew her back there again and again. That very first night, for example, when she returned home to London, her legs stiff from driving, she stood on her doorstep feeling in her pocket for her house keys. What she pulled out instead was a small green business card. She looked at it, in the dim yellow glow of a street lamp. It was a picture of Mary, Mother of God, dressed in a green tartan sari, standing in a seashell, and holding in her hands a grey, vulva-carved stone. All Our Holy Mothers Convent, Papa Astrid. Alice felt her memory stir and stretch. She recognised what it was: a kitsch hotchpotch of cultural appropriation, such as her own Catholic childhood was full of. But she also saw, reaching back through the centuries, the reassuring spiritual devotion she had known once and lost.

Suddenly she remembered the dream she had had on the ferry: Mary, Kali, and women’s vanished prehistoric wisdom, all entwined.

Cwen’s father had seen what she could see. They had sung the same songs. Sometimes he is there still, when she sweeps her mind up and searches for the words she needs above the clouds, or beneath the seaweed, or under the rocks with the squid. She can find him if she listens very carefully to the seashells she brings back from the beach. She sometimes hears him when she crouches through night vigils in the mound. She knows that she still owes him an answer to the question that concerned him. She has failed to pass her knowledge on.

After Cwen died, they buried her, exactly as she asked, with her dagger and divining rods, inside the ancient mound on her island, wrapped in flax cloth. Just in case, they stationed one of their daughters to sit by the spring; and that was clever, for when the visitors started coming, the girl took payment. She picked up Cwen’s cowries from the beach and sold them; she extracted coins for a sip of Cwen’s waters or one of her apples. At first they came from all over the islands. Then they began coming from Bernicia, Deira, Mercia. By the time they were visiting from England as a whole, and Scotland, and even France, Cwen’s spring had a little chapel built over it and a piece of the true cross embedded in the altar. Cwen’s own flax-cloth shroud was exhibited twice a year, around the solstices.