The story begins by introducing George, Harris, Jerome and
Montmorency, a fox terrier. The men are spending an evening in J.'s room,
smoking and discussing illnesses they fancy they suffer from. They conclude
they are all suffering from 'overwork' and need a holiday. A stay in the
country and a sea trip are both considered, then rejected after J. describes
the bad experiences had by his brother-in-law and a friend on sea trips. The
three decide on a boating holiday up the River Thames, from Kingston upon Thames
to Oxford, during which they will camp, notwithstanding Jerome's anecdotes
about previous experiences with tents and camping stoves.
They set off the following Saturday. George must go to work
that morning ("George goes to sleep at a bank from ten to four each day,
except Saturdays, when they wake him up and put him outside at two"), so
J. and Harris make their way to Kingston by train. They are unable to find the
correct train at Waterloo Station (the station's confusing layout was a
well-known theme of Victorian comedy) so they bribe a train driver to take his
train to Kingston, where they collect the hired boat and start the journey. They
meet George up-river at Weybridge.
The remainder of the story describes their river journey and
the incidents that occur. The book's original purpose as a guidebook is
apparent as J., the narrator, describes passing landmarks and villages such as
Hampton Court Palace, Hampton Church, Monkey Island, Magna Carta Island and
Marlow, and muses on historical associations of these places. However, he
frequently digresses into humorous anecdotes that range from the unreliability
of barometers for weather forecasting to the difficulties encountered when
learning to play the Scottish bagpipe. The most frequent topics of J's
anecdotes are river pastimes such as fishing and boating and the difficulties
they presented to those who were inexperienced and unwary and to the three men
on previous boating trips.
The book includes classic comedy set-pieces, such as the
story of two drunken men who slide into the same bed in the dark, the plaster
of paris trout in chapter 17 and the "Irish stew" in chapter 14 –
made by mixing most of the leftovers in the party's food hamper:
I forget the other ingredients, but I know nothing was
wasted; and I remember that, towards the end, Montmorency, who had evinced
great interest in the proceedings throughout, strolled away with an earnest and
thoughtful air, reappearing, a few minutes afterwards, with a dead water-rat in
his mouth, which he evidently wished to present as his contribution to the
dinner; whether in a sarcastic spirit, or with a genuine desire to assist, I
cannot say.
—Chapter XIV