Chief Inspector Isabel Garcia is assigned to lead an investigation into the murder of a young woman found by the river. In this new case, the 5th Brigade will count on an aid of a new element, the Inspector trainee Samuel Lopes.

Isabel and Lopes investigate a second victim, murdered in the same circumstances. Jaime wants the newspaper to focus on this case, keeping its sensationalist course. New clues thicken the mystery about these crimes.

Inspector Isabel Garcia is convinced of the culpability of the main suspect in the murders of the two young women. However Jaime pursues his will to make this case a journalistic scoop, regardless of the consequences for the investigation led by his ex-wife.

Jaime's insistence on disseminating information about the investigation begins to raise public doubts about the effectiveness of the PJ (Polícia Judiciária). Isabel remains focused on proving the culpability of her suspect, which does not allow her to realize the complicated phase that Sara goes through.

While the investigation into the "Strangler of the Scarf" case seems to have reached an impasse, the 5th Brigade can unveil the case of Sérgio and Simone. However, Isabel refuses to surrender to the evidence that his suspect is innocent and continues his investigation against everything and against all.

Another young woman is found dead and the existence of a serial killer in Lisbon seems to be confirmed. After an astonishing confession, the case seems to have come to an end. Meanwhile, through his friends Joana and Bruno, Sarah is envolved in the web of Moisés.

To the astonishment of all but Investigator Isabel Garcia, the case of the serial killer gives a surprising turnaround in Court and the investigation seems to have returned to the zero ground. Meanwhile, and to Isabel's despair, Sara ends up suffering the consequences for having risked dangerous paths. Jaime remains suspicious that Franklin prepares something behind his back and tries to get information through Olivia.

Despite her dismissal from duties, Isabel doesn't resist following the instinct to discover more clues that may incriminate Francisco Morais. In the 5th Brigade, Lopes proves decisive in resolving the case of the trampling. In the Diário Nacional several signs of change are beginning to emerge, leaving Jaime increasingly insecure and isolated. Santos makes an unexpected visit to Sara, but contrary to what both thought they were not alone.

After Olivia's unexpected departure from the Diário Nacional and the publication of the controversial headline, Jaime seems to begin to lose control of the situation. Isabel, removed from the Judiciary, decides to continue the investigation and counts on the support of Lopes. Inácio wants to take back the track of the investigation and uses his influence to alter the pieces of the game and to bet in an improbable substitute to head to the 5ª Brigade.

The Scarf's Strangler strikes back. The investigation resumes in force, this time with the help of Clara, the new member of the 5th Brigade. Isabel, still estranged, tries to follow all the developments with the help of Lopes. Jaime, revolted with his dismissal, takes refuge in home and in the drink, counting only with the support of Carmo.

Santos can not stand the pressure and is removed from the leadership of the Brigade. Inácio finds himself obliged to ask Isabel to return and to dedicate herself exclusively to the capture of the serial killer. Santos, disoriented, tries to find solace in Sara. Lopes begins to piece together the puzzle and thinks he has finally unlocked the mystery behind the Scarf's Strangler case.

While the rest of the Brigade continues with the investigation of the fire case, Isabel and Lopes concentrate exclusively on solving the case of the Scarf's Strangler. Following Lopes's theory, the investigators think they have found Francisco Morais's connection to crime. Sara makes an unexpected discovery that can radically change her life. Under the leadership of Franklin and Olivia, Jaime proudly premieres his new sensationalist program: The People's Punisher.

Moisés and Bruno are involved in the deaths of two young men from their rival neighborhood. Sara, desperate with her pregnancy, makes hasty decisions that could have serious consequences. Isabel and Lopes get access to macabre snuff movies and make an important breakthrough for the investigation. Jaime broadcasts the photograph of Francisco Morais in his new television program, accusing him of being the Scarf's Strangler and lightly inciting to the popular justice.

The information released by the People's Punisher on the identity of the Strangler leaves Francisco Morais furious ... and unpredictable. Moisés incriminates Bruno for the deaths of the two young men and he begins to feel the siege tightening around him. Sara recovers at her father's home and Isabel feels increasingly helpless towards her daughter.

A mega-operation is launched in the Girassóis' neighborhood and everything indicates that Bruno is the main target. The swoop runs in the worst way and Inácio does everything to try to stifle the case, counting on the help of his new ally, Santos. Isabel feels manipulated by Francisco, who seems to be using her as a pawn in an extremely dangerous game...

A boy is brutally murdered at Sara's school and the Fifth Homicide Brigade is called to investigate the case. Isabel feels Francisco Morais getting closer and begins to fear for Sara's safety. Together with Jaime, Carmo decides to investigate the suspicious death of Bruno. Sara thinks she has found a new motivation for her life and decides to go to a casting.

Sara disappeared and Isabel is convinced she was kidnapped by Francisco Morais. With the help of Lopes, she begins a desperate search for her daughter. Jaime uses the program to try to get information, but nothing seems to help. Although her co-workers want to remove her from the case, Isabel relentlessly follows the few clues that could lead her to Sara, unaware that Francisco has not yet performed all the steps of his plan.

A tragic event shakes the way the investigation unfolds. Sara is still missing and the inspectors feel their hands tied. Santos is more and more trapped. Jaime, desperate, joins Lopes to try to find more clues and the two think they have found the place where Francisco is hiding with Sara.

The 5th brigade investigates the place where they think Francisco Morais keeps Sara in captivity.

Meanwhile, Morais begins the online broadcast of the snuff movie that will involve Sara.

Lopes, although distrustful of Santos, and although this one is suspended of the PJ, decides to work together with him in order to find Sara.

Will Sara be saved? And what other surprising outcomes will come from the investigation?