In the "early summer of 1950", Martin Greer is the engineer for a small construction company, Greer and Sons, working with his father. An Army combat engineer for four years during World War II, he and wife Nancy have two young children. Employee George Kress asks Martin to write a letter to the Selective Service System stating that his son, George Jr., is "indispensable" for their company and thus exempt from the draft. Martin reluctantly refuses, and George Jr. joins the Army at the beginning of the Korean War.
Martin's younger brother Jack is in love with college student Carrie Turner, daughter of a judge who is on the local draft board. Despite a trick knee that got him deferred once before, he is drafted. Jack suspects that her father, who feels his daughter can do better, is the reason. Jack and Martin's mother, who lost a son during the last war, asks Martin to write an "indispensable" letter for his brother; he seriously considers it, but does not do so, and Nancy criticizes Jack for his reluctance to serve. Jack joins the Army, where he briefly sees George Jr. before the latter goes to Korea.
George Jr. is listed as missing in action, although his fate isn't revealed, and his father drunkenly blames Martin. Harvey Landrum, Martin's commander in World War II, reenlists and asks Martin to join him, as engineers who know how to build airstrips are scarce. Eligible for exemptions, he initially declines, then agrees, over his wife's objections. Jack and Carrie marry during a furlough before he also goes overseas.
