In 1643, England was in the grip of Civil War, and the town of Plymouth, which was held by Parliament, was besieged by the Royalist army. Widowed Prudence Aish felt that she had enough troubles providing for her family in the face of starvation, and dissuading her young son, Tom, from joining in the war ... Then, unexpectedly, a mysterious soldier inveigled his way into her home and Prudence found herself the unwitting key to a plot that threatened to overthrow the Parliamentarian cause.