Disillusioned by the atrocities of the Wehrmacht, Franz Weber, a young lieutenant from Tyrol, deserts in September 1944 at the southern front in Italy. He is captured and taken to a prisoner of war camp run by the Allies near Naples. Subsequently, the US Office of Strategic Services (OSS) recruits Weber for a spy mission in Tyrol, where he is to accommodate his American colleagues Fred Mayer and Hans Wijnberg, both emigrants, in his hometown near Innsbruck and establish contacts with the Tyrolean resistance for them. At the end of February 1945, the trio of agents manages to parachute over the Stubai Alps and, after overcoming immense difficulties in the heavily snow-covered high mountains, make their way to Oberperfuss. There, they find shelter in attics belonging to Weber's friends. Eventually, Weber's two sisters, Grete and Eva, accommodate Mayer in their apartment in Innsbruck, where he also meets other members of the local resistance. In a German lieutenant's uniform, Mayer manages to gather important information about rail traffic and the Wehrmacht's supply routes from Innsbruck to Italy, which he sends to the OSS headquarters in Bari with the help of his radio operator Wijnberg.