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 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.

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.

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.

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.

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.

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.

Francis observes the growing bond between Mary and Bash, so he turns to Olivia. Meanwhile, Catherine wants to ensure that whoever threatened Mary is captured; Bash seeks to repay his debt; and Kenna tells her friends about her affair with Henry.

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.

In order to get Mary to agree to a marriage, Lord Darnley must demonstrate his loyalty when she voices her concerns about his true intentions. Catherine and Narcisse work to repair King Charles' reputation after rumors spread about his strange behavior and threaten the throne.

Mary has a chance to get out of her engagement, but it requires lying and sentencing a man to death. Meanwhile, Francis and Bash suspect that Tomas may be disguising his real motives.

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 learns from Lola that she has a chance to get to Scotland safely, but she must act quietly and quickly. When Catherine is framed for murder, Mary must decide if she should stay to protect her, which would jeopardize her safe passage to Scotland.

Mary contemplates how to take over the English throne; Elizabeth struggles to find an appropriate suitor to marry. James gets caught up in a scheme orchestrated by John Knox.

Mary and Darnley are at odds as their plan to seize England is put into action. Elizabeth is conflicted about her feelings for Gideon. Catherine's son Henri tries to claim the throne from Charles.

Mary and Francis are taken hostage when the castle falls under siege, and Catherine makes a shocking suggestion in an effort to save them. Meanwhile, Diane reveals to Bash that she's plotting to have him declared legitimate.

Clarissa kidnaps Henry and Catherine's youngest sons, so Catherine turns to Mary and Bash for help. Elsewhere, Lola tries to assist her brother with a debt, but when she gets in over her head, Francis comes to her aid.

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.

Mary pursues justice by launching a counterattack on her conspirators. Elizabeth suffers a major setback, and it turns her world upside down.

A matchmaking event is held for the women in the castle, but Lola doesn't want to take part in it. Meanwhile, Kenna grows frightened when Henry flies into another rage, so she turns to Catherine; and Bash learns firsthand about the horrors of the woods.

Bash saves Francis' life while they're in the woods exploring the latest ominous threat. Meanwhile, Henry becomes obsessed with a servant who won a contest; Greer is seen kissing a kitchen servant; and Henry forces a new couple into a union.

Mary's brother visits and asks her to return to Scotland, but Francis is suspicious of his motives. Meanwhile, Penelope takes command as Henry's mental instability progresses; and Lola is skeptical about Julien's marriage proposal.