Nothing more than an honest italian giallo, this movie tells the torbid story of a string of murders in a small town in the Venice laguna. A young mathematician will find the answer to one of his early nightmares, but he will not like the taste of it. A good music and a good atmosphere don't totally hide a lacking script (a few of the acts of the murderer are without a real, logical explanation), but this is the norm in several of more routinely italian gialli.