In late 1944, as the end of World War II approaches, the Wehrmacht's high command determines to withdraw General Alexander Löhr's Army Group E from the Balkans back to Germany. They plan to supply the tank columns with fuel from a depot in Sarajevo. The Yugoslav partisans' leader in the city, a mysterious man known as Walter, presents a grave danger to the operation's success, and the Germans dispatch Standartenführer von Dietrich of the SD to deal with him. As no one in the city seems to know even how Walter looks, Dietrich manages to have an operative infiltrate the resistance under the guise of Walter himself. The partisans are caught in a deadly game of betrayal, fraud and duplicity while trying to frustrate the Germans' plans.