An American author travels to Rome to promote his latest murder-mystery novel but soon finds himself embroiled in a series of killings that bear an eerie resemblance to the fictional murders in his book. The writer is fascinated and disturbed by these real-life crimes which seem to be influenced by his narratives. As the bodies pile up, the author receives ominous messages from the killer, suggesting a personal connection. Alongside his agent and an enthusiastic fan, the author delves into the mystery, trying to use his knowledge of genre conventions to anticipate the killer's next move. The presence of the author in Rome appears to have sparked the murderer's spree, drawing the line between fiction and reality dangerously thin.

The Roman police, led by an inquisitive detective, are equally baffled by the murder spree and struggle to piece together the clues. They initially suspect a pattern tied to the author's works but find themselves constantly thwarted by the killer's cryptic clues and taunts. As the investigation continues, everyone connected to the author becomes a potential target or suspect, creating a web of paranoia and suspicion. The killer remains elusive, using the city's shadows to their advantage and always staying one step ahead. As the detective and the author become further entwined with the case, the motive behind the murders starts to surface, revealing shocking truths about obsession, jealousy, and the dark side of human nature.