Atholl Fleming - the real "Bulldog Drummond" features only sparingly in this cheerily entertaining and quickly paced jewellery caper. He is involved in a car accident and luckily the brave - but not so useful - "Pennington" (Jack Hulbert) steps up to the plate to help the damsel in distress, in this case "Ann" (Fay Wray). Her problem is that her grandfather - who makes fine necklaces - has been kidnapped by a gang who need to make a counterfeit version of one they intend to steal from the British museum, no less! Soon, the pair are engaged in a perilous search through the tunnels of the London ...