A historical romance from medieval Spain when Christian kingdoms vied with Moslem caliphates in war and intrigue. Lucia grew up within the convent walls of an order of nuns who, with the exception of her tutor and the Mother Superior, have taken a vow of silence. She was unaware that she even had a father until the day he came to retrieve her. The same day a beautiful young woman, screaming and resisting, is brought to the convent and Lucia is taken away by her father to his castle.

She cannot explain why her father has come for her now and decides he must feel obliged to test her resolve before she takes her final vows to become a bride of Christ. Despite the shock of being in the outside world, she enjoys her three days in the castle, and when she is sent off again, she assumes she is returning to the convent. En route two handsome Christian knights waylay her on the road, looking for the girl who had been brought to the convent a few days earlier.

What Lucia does not realize until she crosses the border into the Moslem caliphate of Zaragoza is that her father, in order to ensure the safety of his own borders, has sent her there as a hostage bride to a Moslem prince.