Entering October, Clint Eastwood’s “Changeling” was atop the list of Oscar probables.

But as mid-month approached, poor reviews drove expectations straight into the ground.

Like nearly every promising film released thus far in 2008, “Changeling” appeared to be driving toward yet another disappointment.

However, “Changeling” defies its largely negative critical consensus and is a substantial and well-crafted portrait of personal triumph and tragedy.

“Changeling” is based on the true story of Christine Collins (Angelina Jolie), whose young son Walter was abducted from their Los Angeles home in the autumn of 1926.

Her frantic search seems to come to a happy close nearly two years later, when LAPD captain J.J. Jones (Jeffrey Donovan) informs Christine that her son has been found alive and unharmed in DeKalb, Ill.

But when Jones brings the boy home, Christine immediately knows that the police have found the wrong child.

Embroiled in corruption and desperate for positive press, the LAPD goes to drastic lengths to cover-up its rouse and suppress Christine’s vocal new search.

After accepting aid from outspoken LAPD critic Rev. Gustav Briegleb (John Malkovich), Christine is swiftly thrown in an asylum by the police.

While the LAPD downplays public outcry and Christine wastes away in her cell, a mass grave of murdered children is uncovered in the Los Angeles suburbs, possibly claiming Walter Collins among the dead.

Part David-vs.-Goliath reinvention, part testament to womanly strife, part cold sweat, edge-of-your-seat crime drama, “Changeling” is a complex and soulful picture.

Eastwood hasn’t missed a step behind the lens.

His camera meanders about the film, creeping along crowded streets and sneaking through doorways.

It charges and sidles. It hesitates and withdraws. His direction maintains the poise and deliberation so characteristic of his films.

Ever the actor’s director, Eastwood elicits Jolie’s best turn to date and, more markedly, a surprisingly potent performance from his largely obscure ensemble.

Jolie delivers a rousing performance, emoting feminine vulnerability and vigor at once.

Dressed in Deborah Harper’s concealing costume designs, Jolie is unable to retreat to her sexuality to carry her performance.

Instead, she invokes the innate talent that won her an Oscar for “Girl, Interrupted” in 1999 and hasn’t been seen since.

Jolie possesses a latent tension that throughout the film feels ready to snap at any moment.

She’s potent but tacit, sensual but motherly.

Jolie is given her obligatory Oscar-bait moments of fist-pounding, tear-jerking, plate-throwing emotionality, but for the most part, she maintains disciplined, affecting élan.

Malkovich gives his typical invigorated turn, and a cameo by the underused and underappreciated Amy Ryan (“Gone Baby Gone”) adds to a phenomenal ensemble.

However, the finest performance of the film is from Eddie Alderson.

The 14-year-old Bucks County native who plays Northcutt’s unwilling accomplice delivers a positively momentous performance.

Composed, cunning and mature far beyond his years, Alderson smacks of other powerhouse turns by promising youngsters-turned household names like Christian Bale in “Empire of the Sun” (1987) and Leonardo DiCaprio in “What’s Eating Gilbert Grape” (1993).

Alderson transforms a largely nominal role into a very real, believable, flesh-and-blood character of nearly unbearable heartbreak.

In a word, Alderson is unforgettable. His anonymity is hereby extinguished.

The American moviegoer will hear from this young man again.

Cinematographer Tom Stern photographs a brilliant picture, using his signature earthy pastels and blended light scheme to drape the film in an attractive and understated foreboding.

Pitch-black shadows seep into the movie’s quiet glow, sinking into dimly-lit street corners and contouring the characters’ forlorn faces.

What prevents “Changeling” from achieving the greatness of Eastwood’s recent classics, like “Mystic River” and “Million Dollar Baby,” is its poorly crafted, entirely underwhelming screenplay.

The true story behind “Changeling” is one of the most intriguing and tortuous to be adapted to film in recent memory.

However, Straczynski manages somehow to dilute its full pathos.

Screenwriter J. Michael Straczynski pens some of the most blatantly expository dialogue imaginable.

His script effuses the foul stench of conformism and convention – overwrought, safe and entirely unimaginative.

The dialogue is self-indulgent and painfully predictable.

“All of this has taught me one thing, inspector,” Christine whimpers.

“What’s that, Ms. Collins?” the inspector replies.

“Hope.”

Give me a break.

However, little more could be expected from Straczynski, the writer of such delicious classics as “She-Ra: Princess of Power” and “The Shy Stegosaurus of Cricket Creek.”

The man wrote dialogue for Chuck Norris in “Walker, Texas Ranger,” for Pete’s sake.

A story as rich as this deserved better.

Despite its orthodoxy and lackluster script, “Changeling” nevertheless stands as one of the finer films of this year – a poignant picture of intrepid humanism and graying tragedy.