Bulldog Drummond is a British WWI veteran who longs for some excitement after he returns to the humdrum existence of civilian life. He gets what he's looking for when a girl requests his help in freeing her uncle from a nursing home. She believes the home is just a front and that her uncle is really being held captive while the culprits try to extort his fortune from him.

Bulldog Drummond finds himself immersed in another adventure when he stumbles upon a corpse in the mysterious London mansion of Prince Achmed. Enlisting the help of his old friend Algy and the beautiful Lola, Drummond uncovers a scheme to ship illegal cargo into the country. He must rely on his cunning to survive when the prince offers a reward for his capture.

Drummond goes up against foreign agents who are trying to steal plans for a top-secret aircraft.

Bulldog Drummond forms a gang to rescue his wife and thwart his nemesis, Carl Peterson.