On the night of January 31, 1953, a mountain of water, literally piled up out of the sea by a freak winter hurricane, swept down on the Netherlands, demolishing the dikes protecting the country and wiping a quarter of its landmass from the map. It was the worst natural disaster to strike the Netherlands in three hundred years. The author interweaves the stories of two sister, deftly alternating between the cataclysm and the long years of its grief-strewn aftermath.