In spring, 1941, President Roosevelt orders increased military readiness. Malowski, a good-humored New York City cabbie, drives his cab Betsy to Fort Knox, Tennessee, to enlist. He learns tank mechanics, driving, and weapons firing. On the eve of their first maneuvers, in mid June, a sergeant who used to be a traffic cop turns in Malowski for having the taxi on the base. The base commander tells Malowski he'll have to get rid of her. He stashes Betsy in an old shed, then the maneuvers begin. How will Malowski fare? What about Betsy? Behind Malowski's story, the narrator gives lots of information about the growing power of the U.S. armed forces.