La Sombra Del águila by Arturo Pérez-Reverte

Set during Napoleon's Russian campaign, the story follows a battalion of Spanish soldiers who are conscripted into the French army. These soldiers, originally prisoners of war, find themselves caught in the brutal and chaotic retreat from Moscow. Amidst the harsh conditions and the looming threat of death, they devise a plan to escape by pretending to defect to the Russian side. The narrative combines historical events with dark humor, highlighting the absurdity of war and the resilience of the human spirit in the face of adversity.