It doesn't seem possible that a gung-ho, all-American war machine like John Rambo (Sylvester Stallone) could have spent the first part of the 21st century frittering away his time in the swamps of northern Thailand, wasting his predatory skills on cobras and fish.

Surely 9-11 would have aroused Rambo's righteous wrath and sent him back to Afghanistan, where we last saw Big Bad John in 1988's "Rambo III" fighting the Soviets alongside Islamic insurgents who later ... oh, right. Never mind.

Anyway, "Rambo" begins with its eponymous hero sullenly driving a long boat up and down the Salween River when a group of Christian missionaries led by Sarah (Julie Benz) and Michael Bennett (Paul Schulze) ask him for a ride into the strife-torn jungles of Burma (now called Myanmar), where they can provide aid and comfort to victims of the ongoing civil war between Burmese troops and rebels of the Karen tribe. Rambo grunts "Go home" to these dogged do-gooders and, given the near-bestial behavior exhibited by the Burmese army toward civilians, he may have a point.

Nevertheless, he ferries these folks where they want to go. (Never underestimate the impact of a dewy-eyed blonde like Sarah on a big morose lug.) Of course, the missionaries are there only a week before they're seized by Burmese soldiers and held hostage. One of them is even (shudder) "fed to the pigs."

Do you hate them enough yet? Well, wait. The missionaries' pastor (Ken Howard) hires a motley band of mercenaries to retrieve his endangered flock by any means necessary. Guess who's taking them there? And guess who's asked by the mercenaries' grumpy leader (Graham McTavish) to stay behind with the boat? Now you know Rambo doesn't play that!

Having revived his Rocky Balboa persona two years ago (to middling effect at the box office), Stallone's attempt to jump-start the only other movie franchise that's worked for him may emit a whiff of desperation. This "Rambo" redux at least recognizes that something subtler than the "do-we-get-to-win-this-time" clamor of its predecessors is needed here and, for a while, the layered moodiness applied by Stallone as director and actor works in his movie's favor.

But Stallone's still too much of a showman to resist pushing the audience's buttons. Thus he builds up the Burmese army's wanton butchery to such sadistic levels that by the time Rambo's ready to meet the enemy head-on, we're stoked to see them as savagely mutilated as their victims.

Indeed, the battle sequences are so muddled in execution that we can't tell who's killing whom. Which may have been the point, but knowing Stallone - and Rambo - one doubts that very much.

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