Mary unearths a dark secret being kept by a Spanish prince, so she seeks Catherine's counsel. Meanwhile, suspicion surrounds a new ambassador from English court; and Bash's quest to find a mysterious murderer takes him to Greer's tavern.

Mary takes extreme measures as she tries to stop Francis from catching Condé; a jealous Catherine wants Narcisse to prove himself; Greer makes a decision that could end her relationship with Leith.

Catherine is suspicious that Mary and Condé are having an affair; Francis becomes ill; Bash's life is in peril; Leith is forced to guard Claude.

Mary becomes the temporary leader of France; Catherine asks Narcisse for help beating Mary at her own game; Bash sees a familiar face in the village.

Grateful for a future with a revived Francis, Mary considers signing away her claim to the English throne, and staying in France forever. Catherine learns that Nostradamus has returned -- with a new vision involving Francis' fate.

Mary attempts to help Condé after finding out that the Vatican is after him.

As Francis thinks Mary is turning against France, she risks everything to take Condé down; Catherine meets with Queen Elizabeth; Kenna's secret will seal the fate of her relationship with Bash.

Francis comes to a surprising decision. Mary takes part in a treacherous mission with Lord Condé.

As they prepare for a feast, King Antoine tells Francis and Mary about England's plans for revenge.

Francis makes a surprising move after being threatened by King Antoine; Bash and Kenna's marriage is in trouble; Leith makes a discovery about Greer's new career path.

Mary aligns herself with France as the threat of England looms; Condé makes an audacious move; Kenna and Gen. Renaude grow closer.

Mary makes a bold move to defend her reign in Scotland, which results in a battle royale with her cousin, Elizabeth. Lola is accused of a heinous crime and suffers the drastic consequences. Meanwhile, back in France, Catherine finds that Charles has returned a changed man after paying a price for his mother's relentless quest for power.

Queen Mary, unsure who to trust, tests her brother James to ensure his loyalty after hearing of his meeting with John Knox. Queen Elizabeth agrees to help Lord Darnley, in an attempt to sabotage the powerful suitor’s relationship with Mary.

Bash and Francis come up with a daring plan whilst Mary has a surprising proposal for Claude.

Mary realizes she must help Catherine in her quest to become regent, even at the risk of hurting the alliance with Scotland. Claude is determined to help Leith marry while Elizabeth struggles with the prospect of losing Dudley.

A powerful and dominating Lord learns Mary was responsible for his son's death, he demands retribution. Francis and Lola return to the castle with their new son.

Claude is forced to marry someone selected by Narcisse. Meanwhile, a surprising discovery is made by Elizabeth, and it could alter her reign; and Mary asks Gideon to help her confirm her suspicions about Prince Don Carlos.

An ex-lover of Francis' arrives and brings danger with her, so an uneasy Mary turns to Bash for comfort. Meanwhile, Queen Catherine persuades Aylee to snoop on Mary; and Bash lands in hot water with heretics, who accuse him of disrupting a sacred ritual.

Elizabeth must deal with the political backlash of harboring Catherine in England, while Catherine is imprisoned upon her return to France. Mary is forced to make some difficult decisions about securing Scotland's future and Lola is conflicted in her feelings for Narcisse.

Mary must prioritize her life over her cousin's. Meanwhile, Lola and Elizabeth unexpectedly join forces; Catherine can't escape her past; and Mary and Gideon begin to see each other in a new light.

Shadowy riders have attacked a shepherd, Lord Conde and Bash investigate. Mary reconsiders her relationship with Lola. Leith returns to court.

Mary's mother (guest star Amy Brenneman) returns to advise Mary that her throne is in jeopardy. Mary makes a shocking proposition to Conde, along with a bold move to reclaim her throne. Francis moves closer to Lola after a setback with Mary, while King Antoine (guest star Ben Aldridge) makes Kenna an interesting offer. Megan Follows, Craig Parker, Rose Williams, Celina Sinden, Torrance Coombs and Jonathan Keltz also star.

Gideon shows Mary what life could be like if she chose love over country. Catherine fights to cover King Charles' increasingly erratic behavior, while Claude finds an enemy in her sister Leeza.

Mary must deal with the political repercussions of a potential marriage to Lord Darnley and King Charles disappears, leaving Catherine to pick up the pieces. Elizabeth comes to Gideon's aid, while Claude receives an interesting proposition.

When Darnley gets a surprise visitor, his marriage to Mary hangs in the balance. Elizabeth learns her attempt to stop Mary backfired. Meanwhile, Catherine and Narcisse find King Charles and must convince him to return to the castle.