Lupo Mannaro, based upon the novel by Carlo Lucarelli, is a psycho-thriller revolving around the police commissioner Romeo who is obsessively convinced that the unsuspected Engineer Velasco, well known and respected in his milieu, is a dangerous serial killer. Romeo together with his determined assistant Grazia Negro and police superintendent Rago starts investigating with the help of the famous criminologist Del Gatto. The commissioner will often find himself in difficulty but won't give up the investigation due to his obstinacy and his strong vocation. The case slowly turns itself into a personal challenge between Romeo and Velasco, with unpredictable moves as well as strategies of defence and attack.