If we've learned anything from the Post-Apocalyptic Adventure genre -- and if we haven't learned anything, then what's the point? -- it's that no matter how toxic the air after war/disease/robot uprising destroys society as we know it, no matter how precious water and canned lima beans become, and no matter how difficult it is to find attractive footwear, humankind will still have access to ample amounts of gasoline to fuel their armored SUV deathmobiles. Oh, and there'll always be plenty of ammo. Which is important, because after the apocalypse, there'll be lots of gun battles with poorly dressed, giggling cannibals.

Such has been the law of such films since Mel Gibson chowed down on dog food in The Road Warrior, and the watchable, solidly entertaining The Book of Eli doesn't do much to alter the standard formula. Coming as it does just a few months after the adaptation of Cormac McCarthy's grim novel The Road, it feels rather like the elevator-music version of The Road's soul-crushing, heavy metal rock anthem -- the notes are all the same, but The Book of Eli doesn't make your head hurt.

As Eli, our lone antihero walking this desolate wasteland, Denzel Washington is tough, dignified, and impenetrable. He's headed west on a mission, and he carries a large, leather-bound book from which he reads nightly after spending his days scrounging for supplies and fending off rogue thugs. Elsewhere, in a Deadwood-style outpost of a town, a teeth-gnashing tinhorn dictator named Carnegie (Gary Oldman) is desperate to get his hands on ... you guessed it, a very special book. It's something of a spoiler to tell you exactly what book it is, but if you don't figure it out in the first half hour, you're beyond hope.

While the fundamental story of The Book of Eli offers little that's unpredictable, there are a few small surprises that keep the tale humming along. Mila Kunis, as a town resident who attaches herself to Eli, could have been the standard-issue weak girl who needs saving, but directors Allen and Albert Hughes allow her to not only be capable, but to even kick a little ass herself. And a visit with an older couple who've somehow managed to not only survive but to live a somewhat normal life is interesting not for the reveal of how they live so well -- that twist's a well-trod snooze -- but because they're played by esteemed British actors Michael Gambon and Frances de la Tour. There's also a small turn by musician Tom Waits as the town "engineer," the only fellow who can tinker with gadgets, apparently. While it's nothing that Waits hasn't done before, it's delightful to see him on screen again.

The Hughes Brothers (Menace II Society, Dead Presidents) shoot their film in high style, crafting monotone beauty out of bleak vistas, bleeding the color from the landscape while investing it with deep, rich shadows. One scene, in which Eli takes on a group of vicious brutes armed only with his machete, is shot in silhouette -- the result is a stunningly beautiful image that somehow amplifies the carnage of the fight. Later, a gunfight destroys a clapboard house while the camera swoops in and out of windows, as the Hughes' breathlessly pull out every bit of technical gee-whizzery in their toolbox.

The logic of The Book of Eli's plot crumbles the moment you start to think about it (it's only been 30 years, but people have completely forgotten about religion, and television?) and Eli himself, a character without motivation or backstory, is as vague at the end of the film as he is at the beginning. But the Hughes Brothers have shown, once again, that they're masters of visual storytelling, even if the script is a tad flimsy. It's been nine years since their last film, From Hell -- hopefully they won't make us wait so long for the next one, and perhaps they'll grab a more substantial screenplay while they're at it.