"Changeling" is a gripping true story, stranger than fiction. Indeed, if it weren't based on a factual case, it would almost seem too wild to be believed. Out of this real-life mystery, director Clint Eastwood (2006's "Letters from Iwo Jima") and screenwriter J. Michael Straczynski have concocted an almost epic tale of child loss, police corruption and serial murder set against the backdrop of a burgeoning 1920s and '30s Los Angeles. Eastwood's portrayal of this specific time and place in history is immersive, brought to riveting, well-researched light through the meticulous efforts of production designer James J. Murakami, art director Patrick M. Sullivan Jr. (2005's "Memoirs of a Geisha") and cinematographer Tom Stern (2007's "Things We Lost in the Fire"). For two and a half hours, we cease being in a twenty-first century theater and instead are transported right in the thick of this earlier era.

The timeline begins in March of 1928. Telephone company supervisor Christine Collins (Angelina Jolie) is a doting single mother who, arriving home from work one afternoon, discovers her nine-year-old son, Walter (Gattlin Griffith), is missing. Working with the LAPD and gaining further assistance from pastor and activist Rev. Gustav Briegleb (John Malkovich), a distraught, dedicated Christine sees the disappearance become a big media story. Five months later, word suddenly arrives that Walter has been found with a drifter in Illinois. The boy who gets off the train, however, is not Walter, an observation that Capt. J.J. Jones (Jeffrey Donovan) brushes off. Forced into posing for pictures for the papers, Christine agrees to take the faux-Walter (Devon Conti) home with her—he has nowhere else to go—but is certain, without a shadow of a doubt, that this isn't her son. He's three inches shorter than Walter's last height measurement on the side of the doorframe, his resemblance to him is only passing, and, most revealing, she notices that he is circumcised (Walter was not). Christine's continued urging of the police force to continue to search for her son falls on deaf, decidedly irritated, ears, even after she collects written testimonies from a dentist and a teacher backing up her claims. With his job and the reputation of the entire department on the line, Jones abruptly locks Christine up in a psychiatric institution against her free will.

Christine's personal experiences are enraging to watch unfold, and frustrating, too, in the way that no one of authority (save for Rev. Briegleb) will listen to her. Trapped in a period where women were not taken seriously by professional higher-ups and largely expected to remain compliant, she has no way out of her awful situation because she is not about to sweep the truth under the rug. She will keep searching for Walter until she is unable to. As Christine Collins, Angelina Jolie (2008's "Wanted") gives one of this year's most multilayered and beautiful performances. Aesthetically, Jolie looks perfect for the era, but there is so much beneath the surface of this role that her looks are just compliment to the internal strength, vulnerability and determination she exhibits. The kind of mother who savors her life and parenthood, Christine is a do-gooder who, by putting too much trust in the rest of the world, has the unthinkable happen to her. For every plea, every look, every reaction, every word spoken, every time she bravely tries to hold back the tears, and every time she can't, Jolie is in a master class of acting.

Christine's story ultimately converges with an ongoing side plot detailing the Wineville Chicken Coop Murders. When Detective Lester Ybarra (Michael Kelly) picks up missing 14-year-old Sanford Clark (Eddie Alderson) at the dusty Northcott Ranch in Wineville, California, a devastated Sanford confesses to a string of child slayings that the sociopathic Gordon Northcott (Jason Butler Harner) forced him into taking part in. After Sanford positively IDs Walter's picture as one of the victims, it suddenly sheds a light on the gross ineptitude of the LAPD in regard to Christine's case and adds fuel to the fire of Rev. Briegleb's work in rallying attention to their series of bad judgments and crooked dealings. When Gordon is captured and taken to court, however, his changing story and claims of innocence over Walter's death give Christine a moment of pause. She knows full well what it is like to be falsely accused. Who is to say what happened to her couldn't happen to him?

"Changeling" is one of the fall's first legitimate Oscar contenders, longish at 148 minutes but not a second wasted on extraneous material. Like 2007's "Zodiac" (a film that becomes a richer experience every time it is watched), it covers a comprehensive amount of material and characters and brings such a depth and exacting insight to its treatment that nothing feels washed over or one-note. The script features two minor storytelling contrivances that cannot be specifically mentioned as they would give too much away, but these are quite literally the only notable fabrications within a narrative that is intelligent, absorbing, and avoids mawkishness. Director Clint Eastwood provocatively reveals information as the case matures, never overstepping by spelling things out. He keeps several plot points hauntingly open-ended, full of alternate possibilities—was the boy who claimed to be Walter coerced by the police to act as imposter, or was it his own decision?—and concludes with a series of scenes, each one set months to a few years apart from one another that are necessary in Christine's journey toward moving on with her life without giving up hope.

In addition to Angelina Jolie's sterling turn, the ensemble cast is almost without a blemish. John Malkovich (2006's "Eragon") is the weakest link, though it is a case of miscasting rather than a lacking performance. Malkovich's slow-mannered speech patterns do not immediately lend themselves to the character of Gustav Briegleb, a pastor who does not give up on Christine's cause. As Captain J.J. Jones, who leads the search for Walter and then attempts to shut Christine up when she begins exposing their screw-up to the press, Jeffrey Donovan (2005's "Hitch") is oily, big-headed and maddening (in a good way). Donovan makes you despise Capt. Jones and pity his ignorance. Amy Ryan (2007's "Gone Baby Gone") proves that there are no small parts, only small actors, with her striking supporting work as Carol Dexter, a fellow sane inmate at the psychiatric hospital. Thrown in a crock of an institution more suitable for a horror movie—electric shock therapy is performed regularly, and half the patients aren't even sick—Christine befriends prostitute Carol, who, in turn, offers her sage advice that will help guide her through the rest of the picture.

James Butler Harner (2007's "Next") would be scarily touching if he weren't so unnerving as Gordon Northcott, a sick liar of a man who says he has faced his demons when the chips are down and yet is too cowardly to speak to Christine face-to-face and finally come clean. Eddie Alderson (2007's "Reservation Road") is stunningly acute as young, scared Sanford Clark, whose story of his time with serial killer Gordon Northcott (seen in flashbacks) is harrowing. Newcomer Gattlin Griffith is earnest, sad and wise beyond his years as Walter Collins, putting enough into his early scenes with mother Christine that his disappearance resonates throughout. And finally, Devon Conti (also in his feature debut) is suitably eerie as the boy who says he is Walter, but isn't. Conti always appears to be concealing what he knows just by the subtle looks his character gives Christine, and a sequence where she finally blows up at him and demands to know where her son is is agonizing to behold.

Soundly woven together, all the pieces fascinatingly connecting (or suggesting connection) over the passage of time, "Changeling" never loses steam as the story develops and the characters are faced with seemingly indomitable hurdles. At the head of it all is Angelina Jolie, a virtuous beacon as Christine Collins, whose love for her son and passion toward finding him is always very present in the viewer's mind. In a motion picture of constant indelibility, it is this ravishingly poignant portrait of a woman fighting to be heard while keeping her son's memory alive that lingers most effectively. If there has to be evil on the planet, or right next door, Christine signifies that one's natural propensity for goodness is just as much a crucial constant.