“The Jacket” is a terrific, dark, and cerebral film, and in it Adrian Brody finally proves he’s not a one-hit wonder. To say this is Mr. Brody’s best film since “The Pianist” is not saying much; the majority of his films that have been released since he won the Oscar for his performance in Roman Polanksi’s Holocaust drama were actually filmed before it. But Mr. Brody is even better in “The Jacket” than he was in “The Pianist,” and that really is a shock.

John Maybury’s genre-transcending film, produced by George Clooney and Steven Soderbergh, among others, is reminiscent of mind-benders like “Altered States” and “Twelve Monkeys,” though it easily eclipses the former. The story begins in 1991, during the first Iraq war, where soldier Jack Starks (Mr. Brody) is shot through the head and killed – only he isn’t killed, the medics discover, when one spies him twitching. He is brought back to consciousness, albeit severely shell-shocked and lacking in memory.

Several months later, while hitchhiking in Vermont, Starks accepts a ride with a lone stranger (Brad Renfro), but things turn ugly when they’re pulled over by a highway patrolman. One year later Starks finds himself on trial for the murder of that police officer, a crime he cannot remember taking place, much less committing. Found not guilty by reason of insanity, he is shipped to a mental institution where he’s subjected to such bizarre treatments as being bound into a straitjacket, pumped full of drugs, and inserted into a morgue-drawer-like contraption for hours on end by the inscrutable Dr. Becker (Kris Kristofferson).

During these sessions, Starks somehow finds himself projected forward in time to 2007, where he meets Jackie (Keira Knightley), the grown-up version of a little girl he befriended just before his ill-fated run-in with the law. Together they try to put the pieces together of what happened to Starks. They are racing against the clock, though, as they discover that, back in the “present,” Stark’s death is only 96 hours away.

Massy Tadjedin’s hallucinatory script will no doubt polarize audiences, but it takes care not to present its characters as two-dimensional, particularly its villain, Dr. Becker, who could have been painted as a stereotypical mad scientist, but instead comes across as a worn out, misguided doctor who genuinely believes he’s helping his patients.

Ms. Knightley plays against type as a character substantially darker and more self-destructive than her more recent damsels-in-distress, and Jennifer Jason Leigh and Daniel Craig stand out among supporting players. But it is Mr. Brody who excels; his portrayal is utterly convincing, when it easily could have been campy or ridiculous.

The film is also exceptionally well made. Peter Deming, David Lynch’s regular cinematographer, does fine work. Brian Eno has found a niche in presenting pulsating, unrelenting scores that remain unobtrusive (he did similarly fine work in “Fear X,” released earlier this year), and succeeds again here.

This gripping, exceptional film falters only in its final moments, with a denouement that is a little cheery for its subject matter. The film earns the right to give itself a pessimistic or downbeat finale and should have taken advantage of it. Still, “The Jacket” is by far the best movie to be released so far this year.