After the tragic death of his two-year-old daughter, Stephy, washed up by the tide, and the disappearance of his beloved wife, Elizabeth, missing believed drowned, Ben Tavistock exiles himself from the community. Convinced that nothing or no one can give him solace, he spirals downward in his depression. Allowing only his mother, Rosa, to visit, on this last occasion she finds a letter-unopened and months old-at his request she reads it. Not wanting to give her grieving son more worries, she keeps quiet about the contents; and until she can ascertain what the letter really means, Rosa Tavistock sets out to quiz Ben's long-time friend, Billy Turner.
Meantime, and despite his emotional storm, Ben draws up enough courage to retrace Elizabeth's and Stephy's final movements, from their house to the promenade...