As the film opens, the general has ordered military training exercises and announced, "War starts at midnight." A gung-ho young lieutenant decides that modern warfare doesn't play by the rules, and jumps the gun, leading his men into the General's London club and arresting him in the steam room. When Wynne-Candy bellows, "You bloody young fool--war starts at midnight!" the lieutenant observes that the Nazis do not observe gentleman's agreements, and insults the old man's belly and mustache.

Wynne-Candy is outraged. "You laugh at my big belly but you don't know how I got it! You laugh at my mustache but you don't know why I grew it!" He punches the young lieutenant, wrestles him into a swimming pool--and then, in a flashback of grace and wit, the camera pans along the surface of the water until, at the other end, young Clive Candy emerges. He is thin and without a mustache, and it is 1902.

"The Life and Death of Colonel Blimp" has four story threads. It mourns the passing of a time when professional soldiers observed a code of honor. It argues to the young that the old were young once, too, and contain within them all that the young know, and more. It marks the General's lonely romantic passage through life, in which he seeks the double of the first woman he loved. And it records a friendship between a British officer and a German officer, which spans the crucial years from 1902 to 1942.

This is an audacious enough story idea to begin with, but even more daring in 1942, when London was bombed nightly and the Nazis seemed to be winning the war. Powell at first wanted Laurence Olivier to play his title role, but the screenplay ran into fierce opposition from Winston Churchill, and the Ministry of War refused to release Olivier from military duty. Then Powell cast Roger Livesay, a young actor who had worked for him before, and as the German officer, an emigre Austrian actor named Anton Walbrook.