In London, a shape charge-wielding master criminal comes up with a foolproof plan for robbing a bank and outwitting Scotland Yard's pursuit, but during the getaway he hides his haul in a radio set in the new flat of Capt. Bulldog Drummond (John Howard) and his to-be wife Phyllis Clavering (Heather Angel), leading to a murder, punch-ups, an expedition to France, a night in a French jail cell and a break-out, in a race to reach Bulldog's fiancee