Hugh "Bulldog" Drummond, a British infantry officer in the first World War, finds postwar life as a civilian "incredibly tedious." So he places a classified ad in the newspaper offering his services to anyone who can promise him adventure.

A beautiful young lady answers his ad with the story of two criminal masterminds blackmailing her father. Drummond, seeing an escape from his idle life of boredom, accepts the case, and with it more danger and excitement than he could have imagined. One critic noted the author's "pure energy and derring-do; this book keeps bounding along at breakneck pace on the heedless physical courage" of Bulldog Drummond.