When Catherine de' Medici was forced to marry Henry of Orleans, her's was not the only heart broken. Jeanne of Navarre once dreamed of marrying this same prince, but like Catherine, she must comply with King Francis's political needs. And so both Catherine and Jeanne's lives are set on unwanted paths, destined to cross in affairs of state, love and faith, driving them to become deadly political rivals.

Years later Jeanne is happily married to the dashing but politically inept Antoine de Bourbon, whilst the widowed Catherine continues to be loved by few and feared by many - including her children. But Catherine is now the powerful mother of kings, who will do anything to see her beloved second son, Henry, rule France. As civil war ravages the country and Jeanne fights for the Huguenot cause, Catherine advances along her unholy road, making enemies at every turn...