Simone is blind and by means of a police scanner he listens to the night life of his city Bologna. He listens to people chatting on the Internet without being able to take part. Grazia Negro is a young policewoman who is fragile and strong at the same time and she is determined to reopen some old unsolved murder cases. Bologna is a city in fear of an unknown serial killer called the Iguana who could be anyone or no one and who removes one the identity of each of his victims. He operates at night and always wears a personal stereo turned up high. Simone has often heard his voice: it is unforgettable. Simone decides to help Grazia find the Iguana by tracing his bloody prints and the noises he leaves behind.