The Menace referred to in the title is illicit drugs (Australia at the time was one of the highest consumers of illicit drugs in the world). Mr Grainger has been adducted by a gang, who are just about to take delivery of a shipment of opium, from a passing ship using their fast motor boat. While Detective Scott aided by newspaperman Dick Southern and Frinzi- a young Eurasian dancer do their utmost to stop and capture the gang.