Nicholas Goade, the Scotland Yard detective, takes a well-earned rest after his recent work in arresting single-handed a notorious criminal who had for five years defied the police forces of New York and London. He has been awarded a cheque for 25,000 dollars and six months leave of absence and is enjoying a touring holiday in the West of England in his ancient Ford car with his companion Flip, a small, fat, white dog. But his holiday soon becomes "a busman's holiday", as he himself puts it, as at each turn he is called upon to deal with crimes of murder, blackmail, theft, extortion and and other reprehensible acts which somewhat tend to spoil his (and Flip's) vacation!