A French take on the American western, “The Sisters Brothers” is as tonally offbeat as its eccentric title. By turns melancholy, morbid and deliberately silly, this methodically paced adventure imagines a world that’s both lethal and lethargic. It deals with standard genre materials like desperados, prospectors and stunning landscapes, but never gives them a chance to fulfill their potential as clichés. Scene by scene, it’s difficult to predict whether the proceedings will crackle with violence, swerve into farce, or both.

Set in 1851 Oregon, the action occurs at the tail end of the Gold Rush. The story follows gunman Eli Sisters (John C. Reilly), a sad sack, and his little brother Charlie (Joaquin Phoenix), a hard-drinking grouch, as they pursue a scientist on the run. Hermann Kermit Warm (Riz Ahmed), formerly employed by the Sisterses’ corrupt boss, disappeared with the formula for a compound that may make gold nuggets highly reflective and, thus, easy to pan from the area’s riverbeds.

While the brothers are quite competent at tracking the runaway and shooting dead any other vultures on his trail, Eli yearns for them to retire and open a store together. “Nonsense,” Charlie growls; they’ve inherited “bad blood” from their lunatic father. When Eli corrects him that it was liquor that unbalanced papa, Charlie, who sometimes falls off his horse drunk, says, “Touché.” They bicker a good deal and fight physically. Still, they’re held together by a testy brand of brotherly love, providing each other with the only companionship to be trusted in the isolated frontier.

The fourth wheel on this wagon is John Morris (Jake Gyllenhaal), an eloquent gentleman bounty hunter who tracked down Warm but converted to helping him escape. He expects to work as partners, creating a utopian community based on the (allegedly) learned Warm’s ideals of shared wealth and social cooperation. This sounds more absurd than Eli’s dream of hanging up his holster and starting a family business with trigger-happy Charlie, but the film grants every character carte blanche.

The film is based on a novel by Patrick deWitt and directed by Jacques Audiard, whose 2015 drama “Dheepan” won the top prize in Cannes. He sees les cowboys as saps with six-guns, turning much of the free-flowing bloodshed into grand guignol comedy in the manner of a western by Quentin Tarantino or the Coen brothers. The sharp-eyed cinematography avoids the standard approach of bathing characters in golden sunshine, painting them instead in ink-black chiaroscuro. Nothing here is done the standard, old-fashioned way, including having veteran stars Rutger Hauer and Carol Kane appear in completely unpredictable manners.

While the film feels overlong and at times inches ahead like a glacier, it’s hard to hate. Audiard gives his sometimes-heartbreaking central team of accident-prone misfits a refreshing sense of gravity. In place of the typical Wild West neckerchief, Eli carries a carefully folded scarf apparently given to him long ago by a sweetheart. When he visits a bordello, he doesn’t want the prostitute to do anything more than re-enact that favor while improvising appropriate words of kindness. She’s not a good enough actress to pull off the performance, but Reilly gets what he needs at the climax. It’s at once jolting and delightful, like long stretches of the film itself.

@colincovert