The story of Nanna is set against a dazzlingly detailed 13th-century Northern Europe, where all the power is in the hands of a few mighty lords. There are peasants who are freemen, although their freedom is limited, and thralls (slaves) whose life is worth less than cattle. A woman's value lies between that of a slave and an ox. Into this dark, wild, dangerous world a nobleman's daughter is born and becomes an instant orphan due to treacherous murder and arson. An old woman, believed to be a witch, raises the infant, whom she calls Nanna, sharing all her wisdom with her. When Nanna goes into the world, only her wit and uncanny skills at curing ills saves her from being just another slave girl to be used and abused. She discovers love and passion but also cruelty and lives dominated by fear. As she begins to realize the truth of her identity, she sets out to prove it, thereby becoming a serious threat to a powerful and vicious lord. Her ingenuity has kept her alive so far but will she be able to escape his latest trap when only a slave woman and a nobleman's young son stand between her and certain slow and painful death?