John and Tim begin their epic journey in the upper reaches of the tributaries that feed into the Murray and Darling rivers. Our intrepid adventurers make a futile attempt to launch the Bismarck on the Maranoa River, only to find their launch spot is bone dry! Maranoa, they later discover, means 'river of sand'. Finally there's enough water in the Balonne River to get the tinnie wet, but there's a question over the seaworthiness of the mighty vessel. Making their way down to the Queensland/NSW border, they wander through the parched, brown landscape inspecting the river red gum forests that are dying of thirst, and also uncover the age-old water controversy that people downstream are dirty on people upstream. And that means everyone's dirty on Queensland.