Dodie Fanshaw, rich, much-married former starlet, is staying with her daughter Elena in the idyllic Thames-side village of Markenlea, when a mermaid, a girl who has capsized her boat appears in the garden. Going to a drinks party at the next house, Dodie and Elena discover her neighbour, wealthy Rick Wilbraham, dead, and his new girlfriend Anna standing over him, holding a garden stake she has pulled from his back.
Rick's fortune was made in property development, but he has also netted a huge advance for a first novel from Piers Walls-Farmer's Wallaby publishing house.
There are other suspects: Rick’s cousin Frank, who lives in and works for him, resents the use made of his story in the book; his former wife Elizabeth, fiery and unpredictable, is receiving large alimony but to remarry; his agent and former mistress Serena left the house just before he was found. Several villagers lost money in his schemes when the property market collapsed. How is the mermaid involved? And the typescript of the second book, overdue for delivery, is missing.
Dodie and Elena question everyone, then Anna goes missing, and Dodie discovers another typescript, of what is essentially Rick's novel, with many errors. It seems as though one of Rick's carpenters, Kevin O'Mara, who was Anna's boyfriend before he died in a building accident, wrote the book. Then the mermaid's body is found, she has drowned.