When Lord Darnley surprises Mary with a visit in Scotland, Mary sees a glimmer of a union that could be more than just political. Elizabeth fights to gain allies in her favor and Catherine must work to get Claude back on track by finding her a new husband.

Queen Mary discovers there is a leak amongst her advisors and sets out to uncover the traitor. Queen Elizabeth enlists Narcisse to further her quest for supremacy. Catherine takes desperate measures to regain some of the power she has lost.

Mary must marry again in order to help Scotland, whose welfare she has to prioritize over her heart. Meanwhile, Catherine is accused of poisoning Francis, but Mary believes Catherine is being framed by Narcisse, who's angling to become regent of France.

Mary's feelings for Gideon are hard to suppress, but she does her best as she seeks political allies. Meanwhile, Elizabeth and Greer face gut-wrenching scenarios; Claude is in danger on her wedding night; and a power struggle over the regency continues.

When Mary is presumed dead, Elizabeth asks for Lola's help in taking the Scottish crown for herself; James must defend Mary's throne from John Knox; Mary faces Francis's killer.

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.

After a tragic earthquake hits Scotland, Mary must face John Knox amidst claims that she isn't coming to the aid of her people. Elizabeth takes drastic measures after she is discovered with Gideon, while Charles makes a decision that backfires.

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.

In the series finale, Mary changes the course of history with a decision she makes, and her perilous move for survival causes her to have a stunning realization. Meanwhile, Elizabeth steadies herself for war and becomes the instigator in Mary's demise.

A Portuguese prince offers much-needed aid to Scotland if Mary accepts his marriage proposal and break things off with Francis. Elsewhere, Francis' feelings for Mary lead him to put Bash in a risky situation.

Mary’s life hangs in the balance — Childbirth threatens to take Mary’s life, which leaves her and her unborn child’s safety in jeopardy. Elizabeth discovers that someone in her inner circle was the cause of the death of someone close to her.

Nostradamus shares with Mary his prophecy about a death, which leads Mary to make a big decision concerning Francis. Meanwhile, Clarissa gets brazen as she pursues her goals; and Kenna tells Catherine about Diane's intentions regarding Bash.

Mary uncovers her marriage contract's secret clause, which was added by Catherine and her mother, so she and Francis attempt to persuade the people of Scotland to renounce her mother.

Queen Mary struggles to hold on to her power in Scotland amidst Queen Elizabeth's campaign to sabotage her with the help of a new ally in Queen Catherine. Meanwhile, with Francis' fate at odds and Elizabeth distracted by temptation in her first love, Robert Dudley, both queens struggle to rule.

Charles' coronation nears, forcing Mary to find a suitor who will be her ally. Meanwhile, Lola discovers who's been poisoning Elizabeth; and the castle's serial killer has special plans for Catherine.

Mary, in order to protect Elizabeth, unknowingly puts Gideon’s life in danger. To save him, Mary turns to another Englishman for help – Robert Dudley. Meanwhile, Bash is determined to track down the men behind the threats to Catherine

Mary realizes she must return to Scotland and raise an army to save her throne; Lola gets caught while trying to help Elizabeth find information about her mother.

When Mary arrives in Scotland, she is stunned by the treacherous world it has become and is forced her to keep her royal identity a secret until she learns who she can trust. When Elizabeth jeopardizes her standing with an unbearable new suitor, Lola steps in to help, which causes the Queen to question Lola’s ulterior motives.

Mary and Francis play up their romance after an English envoy expresses doubts about their union. Elsewhere, Catherine seeks to eliminate an individual who's aware of her scheme to destroy Mary.

Mary must decide whether to marry Bash or Francis, who returns accompanied by Lola. Meanwhile, Mary's mother visits and pushes her own agenda, and her mere presence in the castle troubles both Henry and Catherine.

Mary's uncle arrives at the castle and brings dire news about her mother, forcing Mary and Francis to make a tough choice about priorities. Meanwhile, Henry devises a destructive plan; and Bash and Kenna grow closer as they strengthen their forced union.

Mary teams up with Catherine to deal with Henry, whose deranged behavior puts Francis at risk. Elsewhere, Bash resolves to destroy the Darkness after meeting a boy who survived the horror; and a devoted Lola tries to protect Julien.

Princess Claude makes a surprise visit home. The princess is known to be a provocative and reckless young woman. Greer's wedding tour ends earlier than expected.

After Mary receives an urgent message from her ailing mother about the dire situation in Scotland, she finds herself looking to Francis for aid. Catherine finds herself up against Narcisse as she fights to become the regent to Charles. Meanwhile, Elizabeth faces continued pressure to wed.

Mary arrives in France to formalize her arranged marriage to Prince Francis, but complications arise when she meets his attractive half brother and skeptical mother in the series premiere of this historical drama about young monarchs.