While clearing an attic, a young man discovers an old letter from one of his ancestors--a man who never knew his origins and asked his descendants to try to discover his roots. The young man, Tom Temporal, accepts the challenge. In so doing, Tom comes into contact with the scientists who had discovered the time quantum, a previously unknown concept linking different time periods. Investigating his ancestor's roots in nineteenth-century England, Tom not only uncovers disturbing remnants of his family's past but also revives connections with scientists who'd vanished from a nearby location the previous year. What had happened to them? Where had they gone? Karen Butler, now the preeminent theorist of temporality, sits with Tom on the back porch of her parents' Iowa farmhouse and reflects on the true nature of time and its frightening implications.