Commander Stevenson, suffering from unrequited love drives to the coast while very drunk and interrupts some smugglers and informs Scotland Yard.

An ex-con searching for a hidden jewel is assumed by a group of people to be investigating them.

Bulldog Drummond leaves retirement to help a Scotland Yard Sergeant catch thieves armed with radar.

While filling in for injured supersleuth Bulldog Drummond (Atholl Fleming), world-class cricket player Jack Pennington (Jack Hulbert) attempts to foil a criminal mastermind's (Ralph Richardson) impending heist that's targeting a valuable jewel necklace held within the British Museum. This comedic 1930s mystery features daring rescues, intense fistfights and an exciting edge-of-your seat finale aboard a runaway train.