A wealthy Italian businessman is killed in a bomb blast in a car at a quarry, and the Homicide squad discover a bitter and resentful Venuzzi family - two sons, Guido and Tony, vying with each other for their father's favours and advancement. They also discover unhappy employees resentful of their employer's wealth and meanness - in particular a young Aboriginal radical, Gary Willis. The squad's investigation into the Italian community and the small black minority in the area presents a complex montage of internal conflicts and racial hatreds - there are too many motives for too many people. Complicating the issue is vengeance for Venuzzi's death, which doesn't wait for confirmation of the culprit - another must die before the Homicide squad home in on the real murderer.