An attack puts Carla's team to the test, as they have to face unforeseen consequences and which they must face without support from the authorities.

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 more than a year of intense searching, the unit led by Chief Commissioner Carla Torres has arrested one of the most wanted jihadist leaders. But this operation sets in motion a revenge plan against the members of La Unidad.

After confirming that there is a mole, some arrests are made. But new obstacles appear in the Unit's investigation.

Marcos heads the party that searches for the two terrorists all over he area. Now that the fugitives no longer have any weapons or any logistic support, he thinks that they'll soon catch them.

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.

The Unit manages to bring the children of the main suspect to Spain to put pressure on him. The search for the possible mole stalls

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.

Touched by the revenge unleashed against them, the members of the Unit look for a way to protect themselves while going after the members of the terrorist cell, who have not yet completed their plan of attack against Carla's team.

Marcos is attacked while Lua sleeps in her room. Aware that everyone can be a target, they assign a police escort to all the members of the Unit, who must also face the fact that there could be a mole among them.

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.

In Kabul, the clock ticks down as the last flight will leave within the hour, but the Taliban have taken Fazela hostage as retaliation for Carla's betrayal, while Marcos seeks his escape by a land route.

With Aman's help, Marcos takes a leap of faith when the next chance for an escape arises. As the rescue operation for Carla's team begins, Fazela heads for the airport to flee with the Spanish forces, but disaster strikes again.

Marcos finds temporary shelter in a local village; Miriam, Najwa and Massoud remain at their kidnappers' mercy; in Kabul, Afghanistan, Carla refuses to pull out to Pakistan without rescuing her team first.

With her former team kidnapped and held for ransom by local fighters, Carla flies to Afghanistan to get them out; like all in the West, she is stunned by the Taliban's sudden retaking of Kabul, leaving only hours for the rescue mission.

Miriam and Marcos make it to the home of one of Massoud's contacts. Massoud is able to call Fazela, who makes it through to the Spanish to tell them their whereabouts. Carla resorts to a ruse to get to them.

Marcos' local village is a brittle safe-haven while Carla is forced to seek help from an unexpected source to rescue her team. Afghan women like Massoud's wife Fazela are again degraded to near stone-age status.