The daughter of an apothecary and the owner of a secret book of healing arts, Ursula is determined to become a great healer—but her ambition makes her an outsider in the Holy Roman Empire. When she is accused of witchcraft and sentenced to burn at the stake, she is given one chance to save herself; she must march in the People's Crusade to the holy city of Jerusalem. Along with her father and her friend Bruno, Ursula joins thousands of other pilgrims on a harrowing journey that will expose the dark side of the "glorious" Crusades and change her life forever.