Bound by love for their slain adoptive mother, the brothers in "Four Brothers" form a unique quartet that gives John Singleton's film a razor's edge of redemption. It's a thin edge, to be sure, because while Singleton's urban Western pays homage to the Blaxpoitation films of the '70s (as he did with his remake of "Shaft"), it walks a fine line of credibility with a mythic vengeance plot (recalling John Wayne's 1965 hit "The Sons of Katie Elder") that endorses violence as the last resort of a family under siege. When a saintly foster mother (Fionnula Flanagan) is gunned down in a convenience store, her only adopted sons (two white, two black, played respectively by Mark Wahlberg, Garrett Hedlund, Tyrese Gibson and Andre Benjamin) go after the killers, only to discover that their mother's death was not a random event. As they uncover a sticky web of criminal activity involving a local kingpin (Chiwitel Ejiofor), the character-driven plot races toward an inevitable showdown, with ex-con Wahlberg leading the way. Making excellent use of blue collar locations in Detroit, Singleton keeps the action moving fast enough that the film's lack of realism is easily ignored, and the well-drawn characters (including Terrence Howard as a tenacious detective) lend emotional dimension to an otherwise familiar revenge scenario. "Four Brothers" is manipulative, but it's filled with grace notes of rugged working-class humanity, and it definitely holds your attention. "--Jeff Shannon"