Riannon, outcast and female knight, seeks a cause worthy of a chivalric hero in a medieval world of magic and misogyny. Eleanor, a wealthy widow, has given up all hope of finding passionate love and her perfect knight-until she meets Riannon. Aveline, a powerful priestess, needs a warrior for her secret mission of starting a holy war. She binds Riannon with double-edged oaths and a magical sword. A love affair worthy of troubadours' songs clashes with loyalty, intrigue, ambition, and war, tangling the three women in a web that perhaps not even Riannon's sword can cut through.