The Cat o' Nine Tails

An unknown individual infiltrates the Terzi Medical Institute during the night, leaving the staff bewildered. Notably, the break-in occurs without any apparent theft, raising suspicions about the intruder's true intent.

Dr. Calabresi confides in his fiancée, Bianca Merusi, sharing his knowledge about the intruder's identity and motivations. This revelation sets the stage for a dramatic confrontation that ultimately leads to his tragic demise.

In a shocking twist, Dr. Calabresi attempts to blackmail the intruder, leading to a deadly confrontation. The thief reacts violently, pushing Calabresi into the path of an oncoming train, resulting in his untimely death.

A paparazzi photographer captures the horrifying moment of Dr. Calabresi's death, although the identity of the killer remains a mystery. The photograph becomes a crucial piece of evidence in the unfolding investigation.

Reporter Carlo Giordani documents the tragic events surrounding the break-in and Calabresi's death in a gripping article. His piece, featuring the damning photograph, draws attention to the dark undercurrents linking the event to potential foul play.

Franco 'Cookie' Arnò, a blind former star reporter, along with his niece Lori, visit Carlo after reading his article. Franco's instincts kick in as he suspects that the altered photograph may hide deeper truths about the incident.

In a turn of events, the photographer who captured Calabresi's death is murdered before Franco and Carlo can investigate the photograph further. This leads them to understand the dangerous implications of their findings.

Franco and Carlo outline a strategy to tackle nine leads connected to the case, including the scientists at the institute and Terzi's daughter Anna. Their discussion hints at the complexity of the investigation, which they compare to a challenging puzzle.

During an interview with Anna, it is revealed that the institute is researching 'XYY syndrome,' a chromosome with implications for criminal behavior. This discovery introduces a new layer of complexity to the unfolding mystery.

Bianca investigates Calabresi's car and uncovers a note that could identify the killer. She decides to hide the note within her locket for safekeeping, unaware that this choice puts her in imminent danger.

Tragically, Bianca becomes a target as the killer finds her at home. Strangled and her belongings ransacked, the thief searches for the concealed note, showcasing the lengths to which the murderer will go to protect his secrets.

Despite receiving threatening communications from the murderer, Carlo and Franco remain determined to bring the case to light. They uncover crucial connections among the remaining doctors, heightening the tension of the investigation.

In a devastating development, Carlo discovers Dr. Braun’s lifeless body, intensifying their fear that the murderer is actively eliminating witnesses. The stakes are raised as Carlo and Franco grapple with the ever-growing danger surrounding them.

During a chaotic search for Bianca's locket in her crypt, Franco and Carlo confront the murderer who locks Carlo inside. This deadly standoff reveals the killer's desperation, resulting in a violent altercation outside.

In a climactic showdown, Franco corners Casoni, who confesses to his motives behind the break-in related to XYY research. As Franco avenges the harm done to Lori, Casoni is brought to justice, highlighting the film's theme of retribution.