Homicide detectives face a wall of silence when they try to investigate the death of a man at a Melbourne marina. An old salt, Running Jack, is their only witness - but all he saw was the weapon and the body, not the murderer. To solve the baffling crime the police go under cover, with Sen. Det. Redford and Sen. Const. Jill Cregan of the drug squad posing as the owners of a new boat. The detectives eventually find a motive for the murder but are unable to uncover the culprit in the face of stony silence from the tight-knit local boating fraternity, who seem to know more than they are willing to talk about.