A series of murders shakes the autumn city, which cannot be explained for a long time. All the victims are killed with a paratrooper's knife, but there is no connection between them. Does the unpredictable killer choose his victims at random, or do the victims choose him? Exhausted and sleep-deprived homicide detectives are once again racing against time. Until they find out what drives the killer to kill, the city will continue to grow in number.