Thirteen-year-old Kay Telfair believes her life is over when she moves with her family a thousand miles to their new home near the Delaware River in New Jersey. But her life takes an unexpected turn when she meets Anna and discovers a two-centuries-old letter—a letter that could change American history. Before she unravels the letter’s mystery, Kay stumbles headlong into an adventure—confronting fears she’d never experienced, stretching the limits of her friendship with Anna, and forcing a test of Kay’s physical strength that could save her own life.