The Rum Diary should be a better film than it is.

The main problem with it is that there’s not one character with whom we can identify, or who is even remotely likeable.

It’s based on a 1959 novel by Hunter S. Thompson, when the gonzo journalist was just 22. It remained unpublished until 1998.

That’s when Thompson’s longtime friend Johnny Depp persuaded the author to resurrect it, after Depp played Thompson in the film adaptation of Fear and Loathing In Las Vegas.

Set in Puerto Rico in the late ’50s, when it was still a tax haven for U.S. interests and very much an American economic colony, The Rum Diary is semi-autobiographical in nature.

Depp stars as Thompson’s alter ego, Paul Kemp. He’s an alcoholic would-be novelist who is getting his start in journalism after he inflates his resume, parlaying his seminal career with an undistinguished New York newspaper into a job at the San Juan Daily News.

Constantly sporting sunglasses, the persona he cultivates is that of a cynical journalist, hard-bitten before his time.

He’s aloof, brusque and clearly on the make, and soon falls in with the more disreputable elements at the paper. They include staff photographer Bob Sala, an equally cynical employee, played by Michael Rispoli (2009’s Taking of Pelham 123).

There’s also Moberg, played by Giovanni Ribisi, (featured as the head of the mining company in 2009’s Avatar).

He’s a disheveled and wasted wreck, and the paper’s profane and acutely alcoholic crime and religious affairs correspondent, who seems to show up only on paydays to denounce his boss, E.J. Lotterman.

Describing Moberg as “a living example of everything that’s wrong with this paper,” Sala says, “Lotterman can’t fire him because he never sees him; he’s rarely out in daylight… the entire substructure of his brain is eaten away with rum.”

Moberg plays LPs of Hitler’s speeches and indulges in weird hallucinogens.

Added into the mix is Hal Sanderson, a former journalist and now public relations consultant, played by Aaron Eckhart, last seen in Battle Los Angeles.

Sanderson is putting together a shady real-estate deal on an outlying island which the U.S. Navy uses for shelling practice.

His business partners include an intensely anti-communist ex-Marine type who wants to nuke Cuba.

Sanderson seeks to enlist Kemp’s aid to write favourable articles and press releases about his hotel scheme. Kemp, for his part, is sorely tempted, especially after he encounters Sanderson’s blonde girlfriend, Chenault.

Eventually Kemp comes to a crossroads decision-point. He can sell out and tie in with the likes of Sanderson and his band of high-rollers, or sink further into alcoholism with his friends Sala and Moberg.

In the end he does neither, reclaiming his journalistic integrity with words that could well have been uttered by Thompson himself:

“I put the bastards of this world on notice that I do not have their best interests at heart. I will try and speak for my reader; that is my promise, and it will be a voice made of ink and rage.”

There are flashes of prophecy that relate to the film’s late-’50s setting. As he and his friends watch the Nixon-Kennedy presidential debate on TV, Kemp declares, “The Irishman will win. But they won’t let him live.”

Thompson himself was not long for this world, committing suicide in 2005 at the age of 67.

The Rum Diary plays at the Qwanlin Cinema at 7:15 p.m. and 9:30 p.m., and is rated PG for coarse language, violence and nudity.