For one year in her life, Mary Meigs and her long-term lover and friend, Marie-Claire Blais, lived in a menage trois with the beautiful and powerful "Andree." After the end of their stormy three-way relationship, both Marie-Claire and Andree, who are fiction writers, embodied their memories in novels. The Medusa Head comes from the third woman-the autobiographer, who works hard to uncover the truth about that year. The story begins when Marie-Claire meets Andree at a literary event in Paris. They fall in love; and when Mary meets Andree, she falls in love, too. The three of them move to La Salle in Brittany, where Mary and Marie-Claire discover that the beguiling Andree is emotionally complex. In her happy, contented state, Andree is irresistible: intelligent, witty, charming. But Andree is also given to sudden and unexpected mood shifts, the most terrifying of which is her transformation into the "Medusa Head"-a furious, irrational, overpowering figure who must be placated at all costs. Thus, Mary and Marie-Claire are drawn into Andree's emotional labyrinth, from which they find it increasingly difficult to escape.