February 1943, German troops have just capitulated in Stalingrad. Near Marseilles, the Gestapo arrests Multon, one of the Combat resistance fighters whom Lili met at Victoria's.
In Lyon, Lili finds Victoria's daughter Mireille. They go to the printer Velin's, where they meet RENOUVIN (35), a former Action Française member, now in charge of the Free Combat Groups. Together, they plan to break Victoria out of the mental hospital where she is being held, pretending to have lost her mind. It is organized that Lili will stay at the home MARYKA, 40s, and her English companion, JIM. Maryka acts as a go-between, in charge of gathering information from THE BIGWIG, whose silhouette we see, while his face is never revealed. She encodes the information and passes it on to Jim, who sends it to London in Morse code, from a clandestine radio.
At the Gestapo headquarters, Multon faces the cruel KLAUS BARBIE. Interrogated without violence, Multon confesses to everything: his work at Combat, his role, his contacts… while MOOG, a French Alsatian, K30 Gestapo agent, carefully observes him.
Lili visits Victoria in the mental ward and reports her observations to Renouvin, Mireille and Velin. The breakout is scheduled for Christmas night. It is a success. Maryka and Jim celebrate Lili's 19th birthday, and give her earrings exactly like the ones The Kid gave her. Lili is deeply moved. Velin turns up with a mission for Lili: she is to bring a suitcase full of the latest issue of Combat to Victoria, who awaits her in Marseilles. Meanwhile, Maryka and Jim's coded radio messages are being intercepted by a truck outside, where German operators work to locate the illegal radio transmitter.
Back in Paris, where Fabien now lives under a false identity, with his wife and daughter. Despite his new appearance (glasses and a beard), he is arrested by French police, in the Metro.
In Marseilles, Victoria meets Bertin by the seashore and promises him an upcoming delivery of the new issue of Combat. She then meets with MAX, 40s, a long scarf wrapped around his neck, who lets her know that money is on its way to her from London. Her last meeting is with Multon. She is unaware that Moog, the K30 Gestapo agent, is watching them. Moog also spots Lili, approaching with a suitcase for Victoria, filled with copies of the new issue of Combat. Later, Victoria is carrying the suitcase when she spots Multon in a Marseilles street with the Gestapo agents, all heading for Bertin's home. She immediately turns away and rushes off. The Germans descend upon Bertin's home and start searching it. Bertin is wounded in the thigh, but manages to escape.
In the Maquis, The Prof and his crew, now hundreds strong, engage in more and more actions against the Germans: sabotage of communication lines, of means of transportation, of infrastructures, destruction of factories… Mission orders from London are transmitted to The Prof through Combat.
A few weeks later, Lili and Victoria meet in a remote house in the Burgundy countryside – her new hideout. Lili tells her she is headed back to Paris. As for Victoria, she is going to the city of Mâcon, to attend a meeting of the leaders of the United Resistance Movements. When Victoria reaches the meeting place, a horde of Gestapo agents capture her. Thrown in prison, she hangs herself in her cell.
Next day, Lili boards a train to Paris. She sees Didot, whom she met at Victoria's, being arrested by Moog and the traitor Multon. Lili heads to Chalon, at the same time as the Gestapo agents, to get to Maryka and warn everyone. Lili finds out about Victoria's arrest, but knows nothing of her suicide. Maryka sets up a meeting between Lili and The Bigwig.
Next day, Lili goes to the old Traboules neighborhood of Lyon. She reaches a meeting place where two young men in their early twenties, RAVANEL and MORLOT, are waiting for her. They take her to an empty room with a single window overlooking the river Saône, where they leave her by herself. The Bigwig turns up and… it's her own father! He is a Resistance fighter, just like her. The Bigwig's wife, Lili's mother, knows nothing. After their emotional reunion, Lili's father leaves, and Lili remains with Ravanel to give him a description of the two Gestapo agents she saw capturing Didot on the train. Ravanel will get back in touch with her in a few days, so she can confirm the two men's identity. They part ways.
One day, as she walks down a street in Lyon, Lili happens to spot Didot, whom she saw being arrested on the train just a few days earlier. She meets up with Ravanel and identifies Multon and Didot on a photograph. Ravanel confesses to her that this is a catastrophe: a very important meeting is planned in Caluire, where Max is standing in as representative of the Général de Gaulle in France, and leader of the Resistance Movement. Ravanel, Morlot and Lili drive there but watch, thunderstruck, as the Resistance fighters are all arrested. Didot has betrayed them. At the Gestapo headquarters, Barbie mercilessly interrogates Max, whom he calls by his real name: Jean Moulin.
Maryka, Jim and Lili send a coded message to London: the traitor Multon must be killed. Outside, the Gestapo agents locate the building, then the apartment from where the message is being emitted. They burst in. Maryka escapes out the window, but Lili is overcome with vertigo and stops short. She and Jim are captured. Lili is brought in front of Klaus Barbie, who asks her to say whether she recognizes the people on the photos he shows her. A photo of Bertin: Lili nods yes; Victoria: yes; Multon: yes. Barbie calls in Multon, who confirms that he has indeed seen her before, at Victoria's. She is shown more photos. When she sees the last one, Lili has a hard time holding back a hiccup: it is of her father, The Bigwig.