The year is 1665. Fourteen-year-old Gwendoline Riston lives in the village of Letchlade on the upper reaches of the River Thames. Her puritan neighbors have long whispered about Gwendoline - her way with animals, her skill with plants, especially her pale skin and white hair. They believe she is a witch. But her father says she looks like an angel here on earth, and her friend Jack is a loyal companion when the village folk shun her. When a terrible plague hits London, threatening the countryside, no one is safe. The villagers blame Gwendoline. "Purge the pale one " they cry. If that weren't cause enough to be frightened, Gwendoline's friend goes missing and her father sets out to search for him, leaving her hidden away in a secret chamber above the porch at St. Giles Church to keep her safe. With only a meager supply of food, Gwendoline must summon all her courage to survive through the long, hot summer.