After spending her childhood safely hidden away in a monastery, teenage Mary Stuart arrives in France where she has been sent to secure Scotland's strategic alliance by formalising her arranged engagement to the French King's dashing son, Prince Francis.

When Simon, an English envoy, tells Mary that the English are aware of her fragile engagement to Francis, Mary and Francis put on a show to protect their alliance.

When England's armies threaten Scotland's borders, Mary asks King Henry for help but he refuses. Mary then considers making an alliance with Portugal through marriage.

Mary must decide if she is willing to lie and have a man sentenced to death in exchange for being released from her engagement to Prince Francis. Bash and Francis grow suspicious of Tomas' intentions.

One of Francis' former lovers arrives at the castle and brings danger with her. Mary turns to Bash for comfort and Aylee is blackmailed into spying on Mary.

An attempt at scaring Mary causes Queen Catherine to take drastic measures to catch the guilty party. Bash ends up with blood on his hands and Kenna makes a confession.