As Reign Season 3 Episode 1 begins, Mary and her ladies, with the addition of a few new faces, dance by the lake. Mary and Francis are happy and in love once again, having moved past their mutual transgressions during Reign Season 2. Francis has taken up ship building, and his two interests are his boat and his wife. While Mary shares his love, she doesn't share his desire to shirk his courtly duties.
In England, Elizabeth hears from her advisors that the war she wants with Mary and France is going to be expensive. Catherine de Medici has been brought in to Elizabeth's private counsel and she uses her position to usurp Mary. Catherine has called in nobles from French court and plans to use them to help Elizabeth reveal Mary's affair with Conde to the Pope to disempower her.
Lord Narcisse tells Mary and Francis that some of their previously loyal supporters have been turned against them and they risk losing Scotland. Mary wants to use pirates, led my the Martin de Lambert, to steal gold for the crown. He wants 50% of the profits and Lady Greer.
Elizabeth is in love with a married man, Lord Dudley. He asks to be set free from her court, but she refuses.
Narcisse continues pursuing Lola, but Lola will not give in to his love because of Catherine's hatred of her and the fact that he hurt her in order to please Catherine. Narcisse promises to protect her and keep her safe, but she doubts it.
Bash continues to look for Delphine, but has had trouble finding her. His connection to the sorceress continues.
Mary won't agree to give Lady Greer to Martin de Lambert, mostly because Greer is already married. Greer tells Mary to give her blessing and plans to break off the engagement once France has secured more gold. Greer doesn't believe there will be any harm.
Catherine knows of Elizabeth's fondness for Lord Dudley, but Elizabeth asserts her virginity. Catherine believes it's time for Elizabeth to get married, and offers up Prince Charles as a candidate. First, Elizabeth will have to reach out to Francis for his blessing.
Francis doesn't believe Lola should be courted by Narcisse and says he doesn't want Narcisse around John. He says he doesn't want John to grow up thinking Narcisse is what a man should be prompting confusion in Lola. When she presses, he says he forbids a union between Lola and Narcisse.
Mary wants to give Elizabeth an engagement to Charles so the aggressions in Scotland will end. Francis tells her he's dying and she cannot give Charles to Elizabeth.
Martin de Lambert offers a surprising match for Greer but turns out to be a scoundrel. Narcisse tells Lola he is the right man for her and that he'll wait until she can see it too.
News arrives from a page that Catherine hanged herself after the death of a lover, but Mary and Francis recognize that as a decoy. Narcisse brings news that the delegation which traveled to Rome was assassinated and they had correspondence from England.
Mary decides to meet with Elizabeth.
Delphine visits Bash in the night to tell him that she's not guilty of the murder of which she was accused.
Elizabeth is once again advised to marry after Catherine is kidnapped by English Catholics loyal to France. Instead of being rational, Elizabeth turns to Robert Dudley. His wife turns to one of Elizabeth's advisors.
Mary confronts Catherine and Catherine says she turned to Elizabeth for the good of France. Francis orders her put into a cage with Martin's tiger.