A strange and beautiful sea-creature is brought into the marine sanctuary where Sasha works. The sea-girl is kept as an exhibit and for scientific research. But Sasha wants to know more about her - are there more of her kind? What sort of community does she come from? Does she have a family?

There is a story to be told, in exchange for a promise. It is a story of cruelty and grief, of love and longing and pride; the story of Merryn, who makes a traumatic journey from sea and to land, from defiance to finding her true self and the power of sisterhood.

This new fable is from twice Carnegie Medal-winning author, Berlie Doherty. She draws on the folklore of ocean and landscape and, in the language of our oldest tales, weaves the traditional into our modern preoccupations.

Powerful ink and silhouette illustrations by Tamsin Rosewell brighten the tale with a vibrant but classical language of visual storytelling. Rosewell draws on the long heritage of silhouette and paper-cut work for her inspiration, and adds it to her well-known boldness with colour and structure.