In 16th century Europe, two cousins, Mary Stuart, Queen of Scots, and Elizabeth I, Queen of England, find themselves rivals in power and love. Mary, a Catholic widow, returns to her native Scotland to reclaim her rightful throne, but Scotland is a land of stern Protestants under the influence of John Knox. Mary's Catholicism and claim to the English throne threaten Elizabeth's rule. Both queens experience the political and sexual intrigues of court life while trying to assert their dominance in a male-dominated society. The beauty and charisma of Mary make her a formidable opponent, and her claim to the English throne is a serious challenge to Elizabeth's power.

Despite being a contender to the English crown, Mary seeks her cousin Elizabeth's friendship, proposing that they should be allies, but political forces push them apart. The two women navigate a labyrinth of scheming advisors and duplicitous courtiers while grappling with the expectations and limitations placed upon them as female monarchs. Their relationship, shaped by political machinations and personal betrayals, becomes ever more complex as their differing approaches to sovereignty and womanhood come into conflict. Mary's determination to rule Scotland and her ambition to be an accepted sovereign stands in direct opposition to Elizabeth's efforts to consolidate her own power and maintain peace in her kingdom.