Scotland 1561, Mary Stewart, Queen of Scots (Saoirse Ronan) arrives to reclaim her throne. Her rival queen in England, Elizabeth I (Margot Robbie) holds a lesser claim to the throne than Mary but is queen of a larger, more powerful country.
As Mary exerts her rule, the men in her court seek to influence, deceive and dethrone this independent ruler.
Elizabeth and Mary both fear and admire the other. Yet, their treacherous advisors introduce doubt and betrayal to keep them from uniting their countries.
One queen finds bitter loneliness and the other finds her final sacrifice for her country.