Chris Eyre, who made the charmingly offbeat Native American road movie “Smoke Signals” in 1997, presents a darker, edgier view of life on the reservation in “Skins,” but while the tone is different, the film is equally insightful and affecting. There’s a certain raggedness and preachiness to the picture, but ultimately its simplicity and basic integrity shine through and compensate for the flaws.

The film is the story of two loving but often antagonistic brothers. Rudy Yellow Lodge (Eric Schweig) is the responsible one, a member of the Oglala Sioux tribal police force on the Pine Ridge Reservation in South Dakota; Mogie (Graham Greene) is an alcoholic, self-destructive Vietnam veteran unable to take care of his promising seventeen-year old son Herbie (Noah Watts). Rudy, tormented by the aimlessness and mindless violence he sees in the people around him, decides that some vigilante justice might be the answer, and he becomes a nocturnal avenger, brutalizing two youths responsible for another’s death and then setting afire the liquor store that he sees as poisoning the population by preying on their weaknesses. The latter act, however, leads to tragedy when Mogie is seriously injured in the blaze. His hospitalization reveals an even more serious condition, and in the end it’s Rudy who has to undertake the protest against maltreatment of the tribe that Mogie has always dreamed about.

In a precis like this, “Skins” comes across as quite schematic and preachy–perhaps more suited to the printed page, in the form of Adrian C. Louis’ source novel–than to the screen (the adaptation is by Jennifer D. Lyne). But Eyre’s touch is gentle enough that the result doesn’t descend to the merely didactic; he treats his characters without undue sentimentality while making one care about them. The two stars are very good, too. Schweig makes Rudy a moody, complex, somewhat mysterious figure, and Greene, though he pushes a bit too hard at first, gradually settles down and becomes genuinely moving as Mogie. (In one sequence with Watts, he does one of the most convincing drunk scenes ever put on screen.) No one else in the cast stands out, but they’re all at least acceptable.

“Skins” does at times get too explicit in depicting the historical background to the plight of the tribe and to the relationship between Rudy and Mogie (the flashbacks to their youth, some involving their brutal father, are occasionally too obvious). And technically it’s little more than adequate, though the grittiness fits the subject. As a whole, however, it’s a small film of considerable power and effectiveness, well worth searching out.