B-

It’s nothing but a nihilistic potboiler, but Oliver Stone serves up “Savages” with the pulpy verve it needs to be a guilty pleasure. His adaptation of Don Winslow’s novel, about a couple of enterprising California pot producers whose operation attracts the lustful eyes of a brutal Mexican drug cartel, embraces the lurid blend of grit and sheen that passes for style in this sort of fare, moving confidently through a succession of colorfully violent episodes that give its cast ample opportunities for showboating they seize as avidly as the director does.

Taylor Kitsch and Aaron Johnson play Chon and Ben, high-school chums who have formed an unusual—and highly successful—entrepreneurial partnership. Chon, a hard-bitten Special Ops vet who served in both Iraq and Afghanistan, brought back exceptional cannabis seeds from the war zone, which he and Ben, a mellow biology grad, cultivated into the highest-grade weed on the market. Developing a sophisticated production and distribution system with the help of computer wiz Spin (Emile Hirsch) and dirty DEA agent Dennis (John Travolta), they settle down in a spiffy Laguna Beach pad with Olivia, or O (Blake Lively), a easygoing rich girl who’s happy to form a threesome—except for the times when socially-conscious Ben is off “playing Bono,” as one character puts it, with his share of the proceeds in Africa and Indonesia.

So famous does the pair’s product become that it leads to an “offer they can’t refuse” from Elena (Salma Hayek), the brutal cartel head who leaves the dirty work—beheadings, torture and other assorted mayhem—to her chief enforcer, hirsute monster Lado (Benicio Del Toro). When the boys prove hard to get, Elena decides to kidnap O and hold her prisoner to compel the boys to accept her terms.

This naturally doesn’t sit well with Chon and Ben, who retaliate by scheming to buy O’s liberation with money they steal from the cartel while appearing to kowtow to the Mexicans’ demands. And when that proves insufficient, they devise a plot to arrange a straight exchange involving Elena’s playgirl daughter.

That’s only scratches the surface of the double-and-triple crosses the various characters happily indulge in throughout “Savages.” The whole goofily convoluted business culminates in not one but two stand-offs in a desolate stretch of Indian tribal land, in line with O’s admonition, in her opening narration—shades of “Sunset Boulevard”–that just because she’s telling the story doesn’t necessarily means she’s still alive.

Stone uses his cast cannily to make this blithely amoral, totally apolitical yarn push past its manifest implausibility and remain sordid fun. No more is required of Kitsch than the simmering good looks and grim intensity he exhibited in “John Carter” and “Battleship,” but here it’s put to better use, and Johnson’s laid-back affability complements it nicely. Lively gets little chance to exhibit anything beyond damsel-in-distress helplessness, but looks wonderful in her suffering. It’s the supporting villains who enliven things most, though. Hayek manages Elena’s icy malevolence well, but Del Tiro and Travolta really carry the day, giving their characters welcome doses of very dark humor. Happily they ultimately share a scene in which they take play off one another in “Pulp Fiction” fashion.

Stone dresses up the picture with all the visual pizzazz he can muster, courtesy of cinematographer Dan Mindel and editors Joe Hutshing, Stuart Levy and Alex Marquez, who must have worked overtime on the montages and quick cuts. All the other tech credits are topflight.

“Savages” tries to play things in all directions at once, dealing with matters that are horrifyingly real in an offhanded, gruesomely lighthearted fashion, and the penchant to have matters both ways extends to the finale as well. But however deplorable that approach might be in theory, in practice it leaves “Savages” a weirdly enjoyable mix of gore and grim humor. Just don’t expect anything more.