Paul Torregiani, nightwatcher for twenty years, plays a quiet life and monotonous, at night monitoring the holdings of industrial Lucca. One night, after a dispute with Mr Alcide, returns to seek a peace, but he is wounded to death. The investigation starts and the poor Paul is suspected for murder. Meanwhile, the investigation is to expand around Leccetti footwear, where it was found the body, and its occupants. These include the beautiful Nadia, the Russian girl referred Paul is secretly in love. It will not be easy for Paul to prove his innocence...