A young journalist reconstructs for a podcast the story of the first serial killer in Spain's recent history, amid growing tensions over his imminent release from prison. To gain access to the protagonists of the past, he enlists the help of a veteran journalist, who covered the case in her youth. En el círculo del asesino is a fictional series of seven chapters that takes place between the present and the second half of the nineties in the Valencian Community, the years in which the murders took place.