Melilla. Tangiers. Toulouse. In the dark of night, officers from the Spanish, Moroccan and French police forces carry out a synchronized anti-jihadist strike but retaliation looms.

Lack of resources and pressure to catch terrorists increases tensions within La Unidad, whose members also have to deal with the personal problems caused by their exhaustive dedication to police work.

The unexpected disappearance of Myaz sets off the alarms at the Unit. Their spy was based in Salt, near Badalona (Catalonia), so Marcos focuses his team's efforts in that region.

After Ghareeb is dead his son seeks revenge while Carla have a big confession to say to Marcos about her disease.

Carla finds out that there are certain political forces, pressures and scheming at work to replace her as leader of the case and head of the Unit.