 The plot concerns the practice of gambling, which was illegal in the United Kingdom at the time, other than at racecourses.Three dodgy bookies, Alf Tubbe (Ronald Shiner), Flash Harry (Sidney James), and Fred Phipps (Brian Rix), plan to rig a horse race by kidnapping the fancied horse and its French jockey.They stay at a country house hotel near the racecourse, run by Colonel and Mrs Wagstaff, where they conceal the horse Sweet Lavender (and later the jockey) in a hidden cellar.