Coalition strikes weaken the Islamic State, but they are suspected of planning a massive double attack on France.

Ulysse's cyber infiltration helps Lucie and her team finally identify terrorists sent to France with the aim of launching an attack; Vincent must test his source to confirm its reliability.

Lucie is under pressure due to the search for Anis Bahri and Reda Kriket, as the DGSI is confident that the two terrorists are ready to execute their acts; Malika flips a jihadist in Syria with the aim of facilitating the infiltration of the Amniyat.

In the aftermath of the 2015 attacks in Paris, the DGSI and the DGSE must keep their rivalries aside and join forces to prevent future attacks.