Unhappy in her life and relationship, Francesca is inspired by her sighting of a mermaid swimming away to freedom to leave her lover and uproot her life.
She moves to Lewes to stay with Agnes Potts, her loving, eccentric friend. Francesca begins to paint again with Agnes' encouragement, and when her painting of the mermaid is seen by Henry, a local potter, he takes her into his employment.
When Agnes suffers an accident, Francesca must become nurse, chef and companion to her friend. Meanwhile, her ex-lover reappears and attempts to con Henry. Preoccupied by her new duties as Agnes' carer, Francesca finds that suddenly everything she has worked for and built in her new life is put at risk.