What is the main conflict in The Mists of Avalon by Marion Zimmer Bradley?

The Mists of Avalon is an epic tale of love, loyalty, betrayal, kingship, and magic. It takes place over several decades and two generations. It tells the fabled tale of Camelot and the Knights of the Round Table. Taking a different view from the legend, it is told from the perspective of the women of Avalon. These powerful women use their magic and their wiles to fulfill the will of the Goddess and place a king on the throne of Britain, as well as later take him down from it.