A Prophet is a French crime prison film that was written by Thomas Bidegain, Abdel Raouf Dafri, Nicolas Peufailliti and Jacques Audiard, who also directed. The story features Tahar Rahim as convicted immigrant Malik El Djebena of Algeria, who is a petty criminal. Malik is nineteen and has been sentenced to six years in jail for attacking cops. He becomes embroiled with Corsican gangsters under Cesar Luciani (played by Niels Arestrup).
The jail has become divided by Muslims and the Corsicans, but Malik keeps all to himself. Luciani forces Malik to unwillingly assassinate Reyeb, who is a Muslim witness. However, Malik manages to get the Corsicans' protection despite his heritage and begins acting as a servant to them.
Malik's Muslim friend, Ryad, schools him on how to read and write so the two men become very close. Ryad also exposes Malik to his Muslim heritage and introduces them to Tarik and Hassan, two other Muslims. This increases his power in the jail. Malik also strikes an alliance with a drug dealer called Jordi (played by Reda Kateb).
Luciani finds out that Malik has been using furloughs as a way to conduct his own enterprise, so he attacks him. Malik is then sent off to meet another Muslim called Brahim Lattrache in Marseille. He has been involved in a big deal with the Lingherris Italian mob group and Luciani.
Luciani thinks there is a mole in the group and uses Malik to kill the Don of the Corsican mob, Jacky Marcaggi. Ryad and Malik then kill off his bodyguards and throw him into a van with Vettori, Luciani's enemy henchman.
When Malik returns after a furlough, he joins up with the Muslims since he has a strong alliance with them. Two Muslims interfere when Luciani attempts to approach Malik. After Malik is released from jail, Ryad's wife and son are there to meet him. They all leave together with Malik's newest mob associates.