The book opens in 1942, as Helen Anderson prepares breakfast for herself and her sister, Effie, before leaving for her day as a mail carrier in Glen Clova, Scotland. The post office job is one of many given to women while the area’s able-bodied men are away at war. Neither Helen nor Effie ever married, and they live in the family home, which also functions as the town’s schoolhouse. After Helen—or Nell, as she’s called—delivers mail, news of a plane crash nearby spreads through town. As Nell hurries to help the lone survivor, he hands her a photo of a woman before he’s taken away. It’s not long before Nell discovers the woman in the picture, Mathilde, has arrived in Glen Clova to mourn the passing of her sweetheart, one of the crew members who died in the crash. As Nell begins to learn Mathilde’s story, the book flashes periodically back to the years between 1908 and 1917, showing how events during the first World War, including Nell’s work as an ambulance driver and Effie’s secret teen pregnancy, led inevitably to the complex family dynamics through which they are both trying to muddle in the 1940s. Gradually, the sisters discover many secrets and coincidences that help them understand who they are and what sort of lives they want to lead. Told in close third person throughout, the book alternates perspectives between Nell and Effie, also shifting briefly to their mother, Manon, and Mathilde. Full of interesting details about female ambulance drivers at Royaumont Abbey and life in rural Scotland during both world wars, the book offers an unhurried examination of the way secrets can burden their carriers over time. While this emotionally evocative novel would have benefitted from additional setting details to bring the village of Glen Clova more to life, the characters are drawn with depth and nuance. Similarly, although there are too many coincidences to feel entirely credible, the outcome is both satisfying and uplifting.