Occupied France, 1942. Gilles (Nahuel Pérez Biscayart) is arrested by SS soldiers and sent to a camp in Germany. En route to camp, he avoids sudden execution by telling the guards he's not Jewish, but Persian. While the lie temporarily saves him, Gilles is assigned a life-or-death mission of teaching Farsi, a language he doesn't know, to Head of Camp Koch (Lars Eidinger), the officer in charge of the camp's kitchen who dreams of opening a restaurant in Iran once the war is over. Through an ingenious trick, Gilles manages to survive by inventing words of "Farsi" every day and teaching them to Koch. The relationship between the two men sparks jealousy in other prisoners and the SS guards toward Gilles. Meanwhile, Koch's suspicions grow every day, and Gilles struggles with the unfairness of his privileges compared to his fellow prisoners while fighting to maintain his secret and survive.