There are four of them - George, Harris, the writer himself and that dog, Montmorency - all participants in a boating expedition on the Thames. The difficulties and vicissitudes heaped upon these innocents develop to epic proportions as they experience the hazards of the great English waterway. Their problems are in no way diminished by the outrageous behaviour of Montmorency,who lays waste to several riverside communities in the course of their journey.

‘What is a “bummel”?’ said George. ‘How would you translate it?’ ‘A “bummel”,’ I explained, ‘I should describe as a journey, long or short, without an end; the only thing regulating it being the necessity of getting back within a given time to the point from which one started…’

After considerable indecision the bummel takes our heroes to Germany's Black Forest where they manage to disrupt the tranquil way of life usually enjoyed by the denizens, whose curious behaviour they closely observe and record in their account of this second epic journey. Even without that dog, chaos and mayhem reign supreme.