The fourth in the 'Dad and Dave' (On Our Selection) series, Dad Rudd, M.P. sees Dad clash with his neighbour Henry Webster over the need for a higher wall for a dam being constructed in the district. When the local member of the state parliament dies, Dad and Webster stand against each other for the seat. Webster's camp uses every dirty trick to stop Dad Rudd's campaign, but with the help of an old friend Mr Entwhistle, Dad responds with some tricks of his own. On polling day, a major flood threatens the dam wall, while a party of workman on the other side are trapped and certain to die if it collapses. Henry Webster's son Jim (who is in love with Ann Rudd) helps rescue the stranded workers. The emergency sees Dad Rudd vindicated, and he is elected. In his maiden speech to parliament, Dad gives a rousing speech that foreshadows the coming war.
Andrew Pike and Ross Cooper (1980) note that Dad Rudd, M.P. has almost nothing in common with the original Steele Rudd stories, and 'resembles instead the sort of small-town family comedy emphasised by Hollywood's Andy Hardy series. Dad Rudd [becomes] less a naive comic figure than a bastion of middle-class morality, and the story [turns] from the frivolity of the earlier films to an inherently more sober, if rudimentary, allegory on the war in Europe' (p. 249).
The narrative also sees the Rudds attempting to modernise their farm, with unpredictable (and comic) results. Dad Rudd, for example, sets off to buy a new car and returns with an ancient horse-drawn fire-engine. Dave installs a new gas-powered stove for Mum but almost blows the kitchen apart. Among the other comedy interludes scattered through what is essentially a serious plot is a scene in which a team of country fire fighters operate with all the efficiency of the Keystone Kops (Pike and Cooper, p. 249).