London, 1940. Britain is gripped by the terror of the Blitz, forcing Nell Spelman to flee the capital with her young daughter -- leaving behind her husband, Arthur, the clockmaker who keeps Big Ben chiming. When Arthur disappears, Nell is desperate to find him. But her search will lead her into far darker places than she ever imagined... New York, Present Day. When Ellie discovers a beautiful watch that had once belonged to a grandmother she never knew, she becomes determined to find out what happened to her. But as she pieces together the fragments of her grandmother's life, she begins to wonder if the past is better left forgotten...