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.

The wealthy and impulsive Rollo Treadway decides to propose to his beautiful socialite neighbor, Betsy O'Brien. Although Betsy turns Rollo down, he still opts to go on the cruise that he intended as their honeymoon. When circumstances find both Rollo and Betsy on the wrong ship, they end up having adventures on the high seas.