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.