Queen Mary struggles to retain her power as Queen Elizabeth tries to sabotage her -- with help from her new ally, Queen Catherine.
As she works to form political alliances, Mary tries to resist falling for Gideon; Catherine and Narcisse continue to battle for power over the Regency; Claude endures the fight of her life on her wedding night.
When Mary receives word from her mother of the dire situation in Scotland, she turns to Francis for help; Catherine fights to become the regent to Charles; Elizabeth faces pressure to wed.
Mary must keep her royal identity a secret in Scotland; Elizabeth jeopardizes her standing with a suitor; Charles plots against Catherine.
On the season finale, Mary makes a bold move to defend her reign in Scotland, which results in a battle royale with Elizabeth.