“The truth is that none of us is sinless. We all have something to repent of.” So says Catherine de Medici, the last legitimate heir of a brilliant family. Expelled from her native Florence, Catherine becomes the bride of Henry, the son of the King of France, and fights for a worthy position at court, using both the services of the famous clairvoyant Nostradamus, whom she patronizes, and her own prophetic gift. However, in the fortieth year of her life, Catherine loses her husband and is left alone with six children in her arms - in a country torn apart by the ambitions of the treacherous nobility. Thanks to her mental fortitude, extraordinary intelligence and talent for finding compromises, Catherine takes power into her own hands in order to preserve the throne for her sons. She does not know that if she is destined to save France, for this she will have to sacrifice ideals, reputation... and the innermost secret of a battle-hardened heart.