The word antihero could well have been invented for the likes of Jonah Hex.

His story is yet another in the summertime crop of comic books or old TV series adapted into films, this time one of DC Comics’ longest running, but lesser-known series. Maybe that’s because it features a protagonist from out of the American West, rather than from the vast pantheon of super-heroes.

But to peg Jonah Hex into the category of western does it a disservice. For the film combines elements of the traditional western, the supernatural, the American Civil War and the threat of modern terrorism.

Josh Brolin stars in the title role, supported by Megan Fox as his love interest, and John Malkovitch as his nemesis.

Jonah Hex, it turns out, is a battle-weary veteran of the Civil War. It’s 1876, the war has been over for some 10 years, not quite enough to sweep away its bitter aftertaste, and the victorious United States of America, having defeated the Confederate States of America, is about to celebrate its first hundred years as a nation.

Hex has turned to bounty hunting after his stint as a Confederate soldier. He still wears a bedraggled rebel uniform, and his physical appearance is one to evoke fear and repulsion. His lower jaw is marked by a disfiguring hole between his cheek and his lip, the result of a murderous encounter that forms a central part of his tortuous life story.

With his grotesque countenance, his taciturn social manners and his penchant for killing people who cross his path the wrong way, our first impulse is to cast Hex in the role of villain. But as the film inexorably unfolds, we soon find that there’s much more to him than that.

He’s soon pitted against a more sinister, if less threatening-looking foe, in the person of one Quentin Turnbull. Played by Malkovitch, he comes across looking like some kind of hippie displaced in time, with his long flow of greying hair and his eagle-topped walking cane. He and Hex have a long history going back to their wartime experience, since Turnbull, his former commanding officer, holds the bounty hunter responsible for the death of his soldier son, Jeb.

Turnbull has plans to revenge himself against not only Hex, but the entire US government, in a plot to destroy the nation with a secret weapon on the occasion of its centennial.

It’s at this point that the storyline starts to go somewhat off the rails, as Hex is enlisted by Union forces to track down Turnbull and counter his evil plans. He’s aided in his endeavours by not only his prostitute friend, Lilah, played by Megan Fox, but also a talent to extract intelligence from dead people, in a brutal process of grave-opening and physical intimidation.

At many points, I didn’t know quite what to make of Jonah Hex. It evokes memories of Clint Eastwood’s groundbreaking series of films that started with Fistful of Dollars, and concentrated on the psychological development of its main character.

The plot-line is sometimes confusing, but it has a lot of potential if audiences can summon up the patience to stick with it.

Josh Brolin’s performance, although less complex than his central role in No Country For Old Men, is still gripping, and he manages to convey the contradictions between his character’s sinister self-presentation and the backstory of how he got that way.

Less convincing is Malkovitch as Turnbull. As with Megan Fox, we want to know more about how he came to be motivated to take on the forces of power as he does.

We also want to know more of what Fox’s story is, how she comes to occupy the role in Hex’s life that she does, and the film only hints at this. We’re frustrated by the limitations of her role as Hex’s accomplice, and the character development that could enhance her presence in the film is largely missing.

Despite its flaws and the poor box-office performance that has attended them, Jonah Hex is an interesting film that’s well worth seeing. Its offbeat appeal is perhaps marred by the fact that it seems to take on too much, and can’t quite decide whether it’s a western, a terrorist drama or a supernatural thriller.

The power that Brolin brings to his central role, however, gives a certain strength to the film, and sustains it through its many twists and turns. In a blockbuster summer season that has so far been marked by a distinct lack of blockbusters, producing only such bloated duds as Robin Hood, Iron Man 2 and The A-Team, Jonah Hex stands out as an intriguing dark-horse entry.