Among the last bastion of God's holy warriors determined to save Jerusalem from the Muslims, Arn Magnusson of the Knights Templar is renowned as a man of compassion, strength, and faith, even among the enemy Saracens–Saladin and his Muslim followers. Yet, neither time nor distance can lessen Arn's pain of separation from his beloved Cecilia; confined to a cloister back home in western Götaland, his betrothed, the mother of their newborn son, is a pawn in a war between clans vying for control of the crown.

And when an accident of fate brings together Arn and Saladin, an unlikely friendship is forged that will alter the course of the Templar knight's life, and the history of Jerusalem itself.