1942, in German-occupied Paris. Tahar Rahim ('A Prophet') stars as Younes - a young Algerian rogue, living on the wrong side of the law selling goods to fellow North African immigrants on the black market. In a time of oppression and radicalism, Younes is loyal only to himself and his family back home to whom he sends money regularly. His aim is simple - he plans to survive long enough to accumulate enough money to return home a rich man. But his life changes when the police raid his apartment block, taking all of his contraband and arresting him. A deal is placed on the table: Become a spy at the local Mosque, or face an indefinite time in prison. At the Mosque, Younes meets the Algerian singer Salim Halali, and is moved by Salim's beautiful voice and strong personality. A deep friendship develops, and soon after Younes discovers that Salim is Jewish. As Younes goes deeper undercover into the Mosque, keeping a close eye on rector Si Kaddour Ben Ghabrit (Michael Lonsdale), he becomes drawn into a dangerous and morally complex situation - and must face a dilemma between serving his own best interests, or putting himself in mortal danger to save the lives of innocent people.