It is 1847, northern England, and Charles Weightman has been given the unenviable task of overseeing the flooding of Forge Valley, and the eviction of its lingering residents. Resented by the locals and increasingly unconvinced of the wisdom of his appointment as well as the integrity of those who ordered him there, Weightman finds solace only in his neighbour, Mary. Caring for her mad sister has made Mary an outsider, and both she and Weightman find comfort from their mutual isolation. As the winter creeps steadily forward and the waters begin to rise in Forge Valley, it seems that the impending deluge cannot be avoided: not by the locals desperate to save their homes, nor by Weightman, the reluctant vanguard of their destruction.