Agent Malotru (Debailly) is recalled to Paris after six years undercover in Damascus, and ends his affair with Nadia El Mansour. In Algiers, agent Cyclone is arrested, drunk, despite being avowedly teetotal. Debailly struggles to forget Nadia and to return to a more normal working life. He is assigned to train Marina Loiseau, who will work undercover in Iran. Debailly discovers that Nadia is in Paris and resumes contact with her. Meanwhile, agent Cyclone has gone missing in Algeria.

Debailly is still under routine surveillance, whilst resuming his affair with Nadia under his cover identity Paul Lefevbre. He starts to question Nadia's reason for being in Paris. Meanwhile, the DGSE hires psychologist Dr Balmes, and asks her to review his state of mind. Agent Gherbi is exfiltrated from Algiers after hearing about Cyclone, and Marina continues preparing for her mission. The episode closes with a brief scene of Debailly recounting his story while connected to a polygraph.

Marina starts work at the Institute of Earth Physics. A brief scene shows Debailly, connected to a polygraph, continuing to recount his story. The DGSE interrogates Gherbi to confirm he is not also working for Algerian intelligence. Duflot's brother-in-law works undercover in the Sahara Desert. Meanwhile, Nadia's visits to Lefevbre arouse the suspicion of Syrian agent Nadim. Debailly digs into Nadia's background, and confronts her as to why she is really in Paris.

The episode starts with a flashforward of Debailly continuing to explain his story. Nadim investigates Paul Lefevbre, and tells Nadia not to see him again. But he finds them having dinner, and interrogates Lefevbre. Nadia confesses her true reason for being in Paris, and Debailly realises that their relationship puts her in danger. Meanwhile, Reza starts to flirt with Marina, and she has to rebuff his advances. DGSE tries to find out if the Algerians are holding Cyclone, and must stop his mother travelling there to search for him.

DGSE makes contact with Algerians holding Cyclone, and Sisteron goes to Algeria. The Syrians continue to investigate Paul Lefevbre, testing him by mugging him in the street. They also seek help from the Russians. Meanwhile, DGSE puts Marina through a surprise mock interrogation. DGSE is also concerned that Cyclone's capture could have compromised the Sahara Desert operation, in which the Americans are involved. In flashforward, Debailly continues to recount his story to the Americans.