Two resourceful young veterans form a small venture to seek excitement and soon become embroiled in a search for a missing woman and a dangerous packet of diplomatic papers lost after a ship sinking. Their investigation moves through London’s social circles, domestic service, and shadowy conspirators, bringing encounters with an eccentric ally, impersonations, kidnappings, and timed pursuits. Clues gradually reveal the woman’s fate and the true purpose of the documents, forcing the pair into risky improvisations and a final race to prevent the papers falling into hostile hands. The narrative blends lighthearted companionship, suspenseful plotting, and revelations that resolve the mystery and alter the protagonists’ prospects.