In his labyrinthine portrait of a convict turned kingpin, Jacques Audiard ("A Self Made Hero") combines the grittiness of HBO's "Oz" with the shifting loyalties of a Leone western. After assaulting a cop, Malik (riveting newcomer Tahar Rahim) earns a six-year prison bid. Though illiterate, the 19-year-old speaks French and Arabic. Instead of congregating with the Muslim inmates, he keeps to himself, providing a perfect target for Mob boss César (Niels Arestrup of Audiard's "The Beat That My Heart Skipped"), who makes him a "Godfather"-like offer he can't refuse: kill Reyeb (Hichem Yacoubi), an Arab set to testify against the Corsicans, or meet his maker. Malik decides he would prefer to live (in a surrealistic touch, Reyeb's ghost will haunt him for the rest of the film). In return, Luciani offers him protection but stops short of treating him like an equal. When Malik isn't serving coffee and making deliveries, he studies French and Corsu. With what he learns from the mobsters, he befriends two other loners, Ryad (Adel Bencherif) and Jordi the Gypsy (Reda Kateb), and starts a drug-smuggling operation. The years pass, and Malik takes advantage of his parole leaves to work both sides of the fence, and when the authorities transfer César's crew to a different facility, the balance of power shifts from the aging master to the model student. At 149 minutes, "A Prophet" feels more like a miniseries than a movie, but there are no dead spots, no wasted moments, resulting in Audiard's most fully realized vision to date. "--Kathleen C. Fennessy"