Louis' cousin, Princess Louise travels from Italy to Sweden for her upcoming marriage, escorted by the Mukseteers. Her carriage is ambushed by Spanish mercenaries outside of Paris. Rochefort, still a Spanish spy, appears to be behind the attack. Louise is blessed by the archbishop in Paris, where she is targeted again. The assassin kills the bishop by accident and escapes. Rochefort notices the crucifix Aramis' wears from Queen Anne. At the palace, the King has fallen into a depression over the latest attempt on his life, and Rochefort is the only one he will speak with. Louise arrives, but Louis refuses to receive her and asks Rochefort to entertain her during her stay. Marguerite meets with Rochefort after he threatens to reveal her relationship with Aramis. He orders her to steal Aramis' crucifix and bring it to him. Constance tells her husband that she is leaving him for D'Artagnan. When Louise sees how in love they are, she confides in D'Artagnan that she wishes she could find love instead of an arranged marriage. Treville tells Athos that he could recommend him for the new Captain of the Musketeers. Athos and Porthos track down the man who made the crossbow used in one of Louise's attacks, and he reveals that it was confiscated and given to the Red Guard. When they confront Rochefort, he dismisses their suspicions. Milady leaves the palace in disgrace and refuses Athos' charity. Later, she witnesses Louise's footman shoot Captain Treville in the street. Marguerite delivers Ararmis' crucifix to Rochefort, and he reveals that he was the one who gave it to the Queen. Marguerite confides in him that Aramis looks at the Queen the way she wished he'd looked at her. Rochefort orders her to spy on them from now on. Aramis removed the bullet from Treville's back, and after minor surgery, the doctor determines he will live. The Musketeers discover a portrait of Louise, which does not match the woman they have been guarding. They realize that she is an assassin and the bishop was always her target. The chancellor will be the next. Constance's husband arrives to force her home, interrupting Louise's attempt on the chancellor's life. She shoots him, but misses the chancellor. Francesco is killed and Louise is captured. Milady offers to release her if she reveals who hired her. She turns on Rochefort and outs him as a Spanish spy. Treville promises to tell Porthos about his father after he is rested. King Louis appoints Rochefort as first minister in thanks for his service.