This is essentially a Lifetime Network movie, but a pretty good one. Directed without pointless flourishes by Tony Goldwyn, it tells the fact-based story of a Massachusetts woman whose brother was convicted of a murder he swore he didn’t commit. After his appeals were denied, he tried to commit suicide in prison, and to secure his promise never to do so again, his sister, though a high school dropout, agreed to go to law school and pass the bar in order to serve as his attorney and win his release.

The result is one of those tales of feminine achievement in the face of enormous odds that Lifetime thrives on. Not only did Mary Anne Waters pass the bar, but she also located evidence that had been considered lost, got an important witness against her brother to recant, and proved that misconduct on the part of a police officer played a role in the outcome. And she enlists the support of Barry Scheck’s Innocence Project, which brings her mission added clout.

The difference between Goldwyn’s “Conviction”—a title with a double meaning, of course, referring to both the outcome of the man’s trial and his sister’s certitude about his innocence—and what it would have been as a women’s cable movie lies in the director’s straightforward, unforced approach and in the extraordinary cast he’s assembled, all of whom do remarkable work.

Hilary Swank brings her customary steely resolve to Waters, but adds warmth, especially in her scenes with the character’s young sons (Conor Donovan and Owen Campbell), from whom she’s temporarily separated after her obsessive concern with the case leads to her divorce from her unhappy husband (Loren Dean). But she especially comes into her own in the sequences she shares with her brother Kenny, whose mixture of seedy charm and dangerous volatility Sam Rockwell captures brilliantly. (The flashbacks to the characters’ difficult childhood are, unfortunately, less successful, coming across as rather schmaltzy period moments.)

Swank and Rockwell anchor the picture, but the supporting cast is equally strong. Peter Gallagher strikes a pose of genial steadfastness as Scheck, and Minnie Driver one of likable friendship as Betty Anne’s closest friend (and fellow law student), who proves her most reliable helper over the years. Ari Graynor is impressively emotional late in the picture as Kenny’s daughter, who’s long been persuaded of her father’s guilt. And Melissa Leo and Juliette Lewis deliver powerhouse turns, the former as the cop who railroads Kenny and the latter as the angry ex-girlfriend who fingers him for the crime. Leo’s flinty arrogance and Lewis’ trailer-trash calculation both stop just this side of being over-the-top, and insure that at least one of them—if not both—will be front-runners for Oscar nominations.

Technically, the film is solid without being flashy. Cinematographer Adriano Goldman makes good use of Michigan locations that stand in quite convincingly for Massachusetts, and Paul Cantelon’s editing keeps the narrative clear even with the many chronological shifts. The production team—designer Mark Ricker, art director Stephanie Gilliam, set decorator Rena DeAngelo and costume designer Wendy Chuck—manage a convincing period flavor without unduly calling attention to themselves.

There aren’t many surprises in “Conviction”—there would hardly be a story worthy of filming if the heroine’s dogged pursuit of justice weren’t ultimately successful. And the one twist that could have been added—the fact that the actual Kenny died in an accident barely six months after his release—would have ruined the intended sense of uplift beyond repair. But though it’s fairly predictable, the general level of execution—especially on the acting side—takes the material to a higher level.