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.
Princess Claude, a provocative and reckless young woman, makes a surprise visit home; Narcisse pressures Francis; Greer's wedding tour ends earlier than expected.
Following a discovery, Bash and Francis formulate a daring plan; Mary has a radical proposal for Claude; Greer realizes she may be more connected to the Protestant movement than she thought.
Mary's mother (Amy Brenneman) returns with news; Mary has a startling proposition for Condé; a setback with Mary drives Francis closer to Lola; Kenna receives an intriguing offer.
Francis and Mary investigate the poisoning of King Henry; the Duke of Guise returns, placing Catherine in the middle of a love triangle; Greer winds up in an unexpected situation.