The story begins with the three friends, George, Harris and J (the narrator), along with his dog, Montomorency, spending an evening in J’s room discussing their illnesses. They deduce that the reason for their suffering is ‘overwork’. So, they decide to go on a boating holiday, in spite of J’s disinclination towards it.
They go on board the following Saturday. George is supposed to go for work that morning; so, J and Harris reach Kingston by train. At Waterloo station, they bribe a train driver to take the train to Kingston, from where they board their boat and begin their journey. They meet George at Weybridge.
The story goes on with the incidents that include anecdotes told by three of them. The landmarks, historical significance of which are described, are Hampton Court Palace, Monkey Islands, Magna Charta Island and Marlow. The anecdotes include stories about weather forecasts, difficulties related to playing bagpipes, towing a boat, steam launches, punting, sailing and fishing etc. The outcomes of river pastimes, which are a result of inexperience, are described in a humorous manner.