When a travelling salesman dies in a single car accident on a quiet country road, Chief Superintendant Lawson (Joel Tobeck) labels it a drink driving case. But when Constable Parks reveals the corpse's face was blue, Dr Blake (Craig McLachlan) is intrigued. Although the victim's clothes reek of alcohol, Blake concludes that the salesman was not drunk and certainly died before the crash. But how? And why is the face blue?
Dr Blake and Jean (Nadine Garner) head to the boarding house where the dead salesman had been staying. In town for the appliance fair, the state's top vacuum salesmen pitch their new vacuum cleaners to Jean - who is desperate for a new machine. With everyone distracted, Blake snoops around the boarding house and finds a locked basement.
Lawson considers the obvious culprits however Dr Blake follows his own hunches until he makes an alarming discovery that shocks everyone.