Ryan, an American POW, leads his fellow prisoners on a dangerous escape from the Germans in Italy. Having seemingly made errors of judgement, Ryan has to win the support of the mainly British soldiers he is commanding.

In August 1943, Maj. Eric Fincham, a professional British soldier, is the ranking Allied officer in an Italian prisoner-of-war camp. He has tried to lead escapes but has always failed, and now he must relinquish his leadership to American Col. Joseph L. Ryan. Ryan's hard manner wins him the nickname "Von Ryan," and though he obtains better living conditions for his fellow prisoners, he is not popular among them. Ryan renews the plans for escape, and with Italian cooperation the prisoners take over a freight train transporting them into Germany and flee across Italy toward Switzerland. They are chased by a German troop train, attacked by German aircraft, and pursued by another Nazi train. Ryan kills Gabriella, an Italian collaborator, and he himself is killed, though most of the men arrive safely in Switzerland.