After the opening scene, a firing squad execution, an unseen narrator announces that Decision Before Dawn will explain why a spy risks his life to betray his own country. The picture never quite does this, but in trying, Twentieth Century Fox has produced a semi-documentary melodrama that can be best described in superlatives.

The plot revolves around three members of an American intelligence team out to obtain information on German troop movements behind the Rhine. Leader of the team is an American captain. He has no political convictions. He spies because he's ordered to. Tiger, the second agent, is a German POW who has switched sides for better pay. But the central figure is "Happy," a sad-eyed, 19 year old medic, played by Austrian Oskar Werner. He becomes a traitor because he believes in "a life where people are free."

In bringing these men together, the picture does an excellent job of showing how American Intelligence recruited, trained, and equipped German prisoners for espionage work, and smuggled them into Germany. Happy's sensitive acting puts the factual details in a meaningful human context.

Much of the picture centers on Happy's "tourist mission" through Germany from the south up to Mannheim. These sequences, actually filmed in Germany, provide a vivid picture of towns and people gutted by war. The attitudes with which Germany met defeat are typified by the characters Happy encounters. There is a corrupt SS sergeant having his last fling in a sordid military brothel, an attractive girl turned to prostitution, a Prussian general who uses the noose to maintain discipline to the last. These characters, against a background of bombed out and burning buildings, give a most effective impression of stark, demoralizing realism. Happy takes it all in with the disillusioned expression of a man who recognizes evil, but can see no answer.

After a series of hairsbreath but believable escapes from the Gestapo, Happy reaches Mannheim and delivers his information to his teammates. Then he surrenders himself to cover the American's return to headquarters.

Happy's motives for treason and his final sacrifice are never convincingly shown, but expert photography and realistic acting make Decision Before Dawn one of the year's best melodramas.