Historian Anna Bennett has a book to write. She also has an insomniac toddler, a precocious, death-obsessed seven-year-old, and a frequently absent ecologist husband who has brought them all to Colsay, a desolate island in the Hebrides, so he can count the puffins. Ferociously sleep-deprived, torn between mothering and her desire for the pleasures of work and solitude, Anna becomes haunted by the discovery of a baby's skeleton in the garden of their house.