Polly and Frank are young and in love, a lifetime together before them. But one evening in 1980, as the Texas sun sets over their shoulders, the world is suddenly pulled apart by a deadly virus. Within months, Frank is dying. Polly can save him, but only if she agrees to a radical plan: to time travel to 1993 for a corporation who can fund his life-saving treatment. She can only go forward, she cannot go back. And she must leave everything she loves behind, including Frank. All they have is the promise of a future together: they will find each other again in twelve years' time, in Galveston, Texas, where the sea begins. But when something goes wrong and Polly arrives late, Frank is nowhere to be found. Completely alone, Polly must navigate a terrifying new world to find him, and to discover if their love has endured.