When a delirious prisoner on death row tells Dr Blake he is innocent of the police shooting for which he is soon to hang, Blake is stunned - and believes him. But no one else seems interested in uncovering the truth.
Irish immigrant Sean McBride is accused of shooting a policeman, Clive Cooper. Sealing his fate on death row, Sean originally pleaded guilty to the crime and refused to defend himself in court.
The town is divided over the rights and wrongs of capital punishment. The police rally around their own, determined to get 'justice'.
District Nurse Mattie O'Brien is vehemently against capital punishment and finds herself at loggerheads with friend Danny Parks. Constable Parks arrived at the crime scene just minutes after the shooting that fateful day and Sean McBride even shot at him. Danny desperately wants to back his copper mates but starts to doubt the evidence as Dr Blake asks more and more pertinent questions.
The closer Blake gets to the shocking truth, the tighter the circle closes.