Historian Anna has a book to write. She also has an insomniac toddler, a death-obsessed seven-year-old, and a frequently absent ecologist husband who has brought them to a desolate island in the Hebrides so he can count the puffins. Sleep-deprived and torn between mothering and her desire for work and solitude, Anna becomes haunted by the discovery of a baby's skeleton. Her narrative is punctuated by letters written 200 years before by a midwife trying to introduce modern medicine to the islanders. The lives of these characters intersect unexpectedly in this deeply moving but also at times blackly funny story.