An unknown, black-gloved assailant plans a murder and takes photos of a potential victim as the movie begins.
Sam helplessly witnesses the attempted murder of Monica Ranieri.
Sam and the investigators attempt to decipher the voices in the two phone calls made by the assailant.
The assailant calls Morosini and threatens him to stop the investigation or there will be be a fifth murder.
The assailant calls Sam at his apartment, warning him to abandon the investigation or his girlfriend will be the next victim.
Sam inspects the painting that the assailant may have bought.
As the investigators inspect the scene of Monica's attempted murder, Sam tries to remember what he saw.
Sam visits the antiques shop where one of the victims worked and tries to track down the painting bought by the assailant.
Sam is attacked on his way home.
The assailant attacks the 4th victim in her apartment, in the style of the painting from the antique store.
The assailant stalks the 4th victim at the racetracks.
Morosini and a psychologist sit down for an interview to discuss Monica Ranieri.
The assailant attempts to murder Guilia.
Sam tries to find Guilia.
Sam and Guilia go over the names and murder photos of the assailant's victims.
While looking for clues, Sam discovers another murdered body.
Sam recounts to Guilia how he witnessed the attempted murder and tries to make sense of his flashbacks.
Sam collects his paycheck and heads back to his apartment.
Sam discusses the revelations made by analysing the assailant's glove with the investigators.
Sam and Morosini inspect previous convicts to understand the assailant better.
Sam and Guilia are attacked and chased by an unknown accomplice of the assailant, but after outrunning him, Sam loses him to a crowd of similarly-dressed men at a boxing convention.
Sam arrives at the Ranieri's apartment to talk to Alberto.
Sam finds out the identity of the assailant.
Sam is attacked by Monica in the gallery.