In Rome, after leaving a nightclub, a teenager is killed in a car accident. Everything indicates that it was a simple collision, but Corso, a former cop who's now a private detective, is convinced otherwise. Michelle, the teenager's mother and Corso's ex-girlfriend, is now with Argento, a powerful and influential lawyer. During the investigation, the corpse of an engineer, apparently a close associate of Argento, is discovered. Corruption, telephone surveillance, spying, the settling of scores: the investigation proves difficult for Corso, who strives to bring to light the truth about Michelle's son's death.