Following a mysterious decapitation (via mechanical digger) of an insurance investigator, Police Inspector Peretti (George Hilton) is put onto the case. Slowly more people are found dead... a man suposedly commits suicide, a women is strangled, another attacked in her flat... but all the clues lead to an unsolved case of kidnapping and murder. Can Peretti find the murderer, if his major clue is a little girls drawing???