As Mary's upcoming wedding looms, a terrible tragedy pushes Mary and Darnley apart, forcing Mary to enlist in Catherine's help. Elizabeth encounters a traitor to Spain, who petitions her to support an expedition to the New World.
Mary and Darnley wed in a lavish affair, which proves to be a successful decision in regards to her political standing. James makes an interesting discovery about Greer, while Elizabeth frantically tries to salvage England's power.
As Mary strategizes ways to take over the English throne, Elizabeth struggles to find an appropriate suitor to marry. Meanwhile, James gets caught up in a scheme orchestrated by John Knox and has to deal with the tragic aftermath.
Mary and Darnley are at odds as they put their plan to seize England into action. Elizabeth is conflicted about her feelings for Gideon as she attempts to find a Catholic to marry. Catherine's son Henri (guest star Nick Slater) attempts to claim the throne from Charles with the support of Spain and Narcisse.
Darnley teams up with John Knox to strip Mary of her throne, which will leave a close friend of Mary's dead. Elizabeth must banish Gideon from court at the request of her future husband, while Charles takes a bold stance against his brother Henri (guest star Nick Slater).
