Plot summary
Queen Mary suggests that Princess Claude, who is Catholic, and Prince Louis, who has converted to Protestantism, be wed as a symbol of interfaith relations. King Francis accepts this suggestion, but only so that it will distress Lord Narcisse and trick him into revealing where he's hiding Montgomery, the last witness who knows that King Francis had killed his own father of his own will.
Prince Louis seemingly agrees to the engagement with Princess Claude, but leaves a letter for Mary and quits the castle. While King Francis and Bash are away in an attempt to destroy Sir Montgomery, a group of Protestant assassins sneak into the castle.
Frustrated at being unable to find King Francis, one of the assassins rapes Queen Mary. After she is comforted by her mother-in-law, who helps her hide the evidence and present a strong front to the people of France. King Francis, when he returns, is distraught and blames himself. Castleroy and Lady Greer discover that their charity donations were used to fund the assassination attempt. Lord Narcisse confides to Lady Lola that he is appalled at the Protestants' desperation and regrets to have brought things this far.
Credits
Adapted from Wikipedia contributors, Reign season 2. HTML formatting and reference markers removed.