Britishers of every class band together to repel the German Blitz.

Britain is at peace with no thought of war when the Nazis begins regimenting their forces for war. Unaware of the brooding German forces, squadron leader W. C. Richardson, his wife, and Bobby, a young relative from Canada who has come to join Britain's air force, watch the Hendron Air Pageant of 1937 with interest and delight. The calm is shattered, however, when events in Europe build into the maelstrom of war as Hitler violates the Rhur, annexes Austria and marches into Czechoslovakia and Poland. When England's Prime Minister makes his historic broadcast declaring war, the country is ready. After bidding farewell to Mrs. Richardson and June, Bobby's sweetheart, Richardson and Bobby leave for the RAF station. Left alone to listen to the mournful wail of the air raid siren, the two women go to work at the First Aid station. Meanwhile, at the front, Britain's bombers launch the Kiel Canal raid on a flotilla of German gunboats. After ten breathless minutes, the pilots return to their base, triumphant. Richardson, now a wing commander, is control officer at a fighter station to which Bobby is attached. After an exacting period of duty, Richardson returns home exhausted. Soon afterward, Mrs. Richardson comes home from duty at the First Aid post. It is daylight already, and they drive along the river and come to rest beneath a magnificent old tree, where she speaks of the high price they must pay for remaining free.