Isabel Garcia, chief inspector of the PJ, is faced with the biggest challenge of her career when she was assigned to lead the investigation of what will be the most important police case in Portugal in the last 20 years: the violent serial killings that plague the city. Samuel Lopes, trainee inspector with a degree in Criminal Psychology, joins the Garcia Brigade where he will have to earn his place and the respect of more experienced inspectors. Living with the intern inspector helps Garcia to better understand his daughter Sara, a 16-year-old teenager who was the result of a failed marriage with the relentless journalist Jaime.