The excitement at the end of last week's episode, it turns out, wasn't because of a death. Catherine fooled us into expecting a poisoning, but it was an explosion in the kitchen. The cook, who loaded the tampered bread pan into the oven, is injured, and Rahima, the maid to Catherine de Medici, is blamed for it. While she protests her innocence, we know she planted the substance (provided by Catherine) that caused the explosion.
Catherine: “Be careful not to cloud your judgment. One is never safe when one is in love.”
As the servants discuss Rahima's punishment, Catherine appears on the kitchen steps to complain about breakfast being late. She warns them that Rahima is under her protection and whisks her away to choose a new dress to celebrate her victory. As they stroll the grounds, a man smiles approvingly at Rahima, and Catherine comments favorably on his interest. But she warns the girl against letting it go to her head. No one warned her of the hazards of love when she was young, and she wished they had.
Young Catherine sighs over Henri's letters, away at war for almost a year. His letters rhapsodize about the air and light of Italy and the honor of serving her, fighting for the lands owed him by her dowry. As she wanders the forest, she finds Ruggieri's lair, complete with a magical mirror. As they discuss if he fulfilled her last request, he says if she asks another, there will be a price to pay, and she doesn't get to choose. But the castle bells ring, which only means one thing: Henri's back! She runs to the palace to primp and meet him.
Henri is greeted with approval and warm praise from his father, despite bringing his mistress, Filippa (Elissa Alloula), and their child, Diane (named for de Poitiers). Catherine, once alone, dissolves into tears. Sebastio comforts her, saying it's what men do at war, and it doesn't mean anything, but she burns Henri's letters. Anxious to maintain the status quo, Diane visits to offer a truce. Catherine must now produce a son; Diane shall deal with Filippa. Diane tosses the last letter onto the fire, and Catherine bursts into tears again.
Meanwhile, the King celebrates Henri's success, replacing Francis as the favorite prince. But Montmorency, the only advisor with any brains or integrity, suggests that they cede half of the captured lands back to the Pope to keep the peace in Europe and concentrate on domestic issues, the growing tension between Catholics and Protestants in France. The King reluctantly agrees to give back some, but not half.
The King has also become fond of Catherine, realizing she's smarter than her husband and that it was her idea to ally with the Sultan to claim the Italian provinces. Diane might be the one to visit Filippa, admire the baby by an open window, and suggest a nice place in a convent after Filippa tells her Henri, tactless as ever, wants Diane to act as a grandmother. However, it's almost certainly the King's decision to send Filippa and the baby away, to Catherine's relief.
"I didn't think it could get any worse. I was wrong," Catherine tells us as she and Henri are subjected to a medical exam in front of the King, the Queen, and Diane, at the latter's suggestion. The doctor (Jean Fernel) uncannily foreshadows the use of emojis with melon and eggplant, demonstrating changing positions to ensure conception. Another excruciating sex scene follows (without the audience). Henri apologizes and scampers off, presumably for a restorative session of Bible study with Diane.
Why is Henri, in thrall to that notorious mistress of the erotic arts, so totally clueless? It doesn't matter: Catherine believes she may be pregnant. Meanwhile, Marthe and Francis' relationship continues. He talks about being hostages of the Sultan with Henri, abused by the guards. Francis' tutor was a little person and kind. Marthe says her parents abandoned her. They are interrupted, and Francis says to hide, so she overhears the Duke of Guise saying Henri's rise is a threat, and the best solution for Francis is an "accident" to befall Catherine.
After the King and the Holy Roman Emperor's ambassador negotiate the deal regarding the Italian states, Francis publicly attacks Catherine, describing her as a curse on their family. He's always disliked and abused her, but his father's partiality for Henri and Catherine has driven him too far. The King is furious and hits him. Catherine, upset, leaves the court for her bedroom and discovers she is not pregnant, missing the King's violent assault on Francis. Diane comforts her and tells her own marriage horror story.
Marthe attempts to tend to Francis, but he takes out his anger on her with typical cruelty. When Catherine next takes a ride into the forest, she's attacked but fights off her assailant, and Henri finds her injured. Shocked, he tells the King she is in danger. Meanwhile, Catherine visits Ruggieri: she must get pregnant. He gives her a book of potions and warns her to be careful with mushrooms. She takes the book to a flustered Sebastio. He has a private appointment with the Queen (the mind boggles) and hustles her out, leaving the book on a table.
Francis collapses during a tennis game with Henri and asks for water. Marthe shrugs; she's not going to help him, so Sebastio brings him a drink while Henri tries to help his sick brother. But Francis stops breathing, and the royal doctor reports he died of heart failure. The King believes he was poisoned and blames the Queen (his gut reaction to most problems) before charging Montmorency to find the murderer. Italians are notorious prisoners, and Catherine is in trouble as Montmorency discovers the book she left in Sebastio's room.
However, if Catherine is accused of murder, it could cause war, and Montmorency is opposed to that. Yet, someone must be blamed. Montmorency is banished from the court while Sebastio suffers a nasty public execution, during which Catherine has a panic attack and throws up, and really, who can blame her? But it's not just seeing her best friend die horribly; she's finally pregnant. Henri is now the Dauphin, the heir to the French throne, and the King is delighted Catherine is pregnant, ensuring the dynasty for another generation.
Catherine's remaining servants are nervous, and rightly so. If she could do that to Sebastio, the one closest to her, whose relationship with her was always intimate and affectionate, what chance do they have of surviving? Rahima, who has listened to Catherine spellbound, does not seem to draw any conclusions about her own safety, even though she's hearing some deep, dark secrets. As the story winds down, they meet up with Mary, the future Queen of Scots, Catherine's widowed daughter-in-law (Antonia Clarke).
Rahima discovers Catherine gave her Mary's gown. She and her four ladies are all dressed in white, and they are all called Mary. "To avoid confusion," Catherine murmurs. "It's so convenient." But Mary, despite the white gowns she claims are inspired by the Virgin Mary, reveals she is a true product of the French court, determined to grab power at any cost. Once Catherine and Rahima are out of hearing, she tells her four Marys that if Charles becomes King, the true power running France will be Catherine, and Mary will do anything to stop her.