As an action star, Tony Jaa seems capable of doing almost anything, be it jumping through hoops, running on the backs of stampeding elephants or taking down a much-larger opponent with his hands or feet.

There's a good reason why he's been compared favorably with Hong Kong stars Jackie Chan and Jet Li in that regard. However, as an actor, Jaa pales in comparison to both the charismatic Chan and Jet.

The Thai star may be even worse at filmmaking, as evidenced by "Ong Bak 2," which he co-directed. It's an incoherent, would-be martial-arts epic with only a handful of action sequences in its favor.

This supposed "prequel" retells a few 15th-century Thai legends, and stars Jaa as Tien, the son of a beloved warrior-scholar.

In the days after his father's murder, Tien becomes a fugitive. And he's been trained in martial-arts and other forms of discipline, as he seeks revenge on the responsible parties.

Jaa and screenwriter/co-director Panna Rittikrai wait till the midway point to even explain the relationships between the plot and the characters. (Its connection to the original, 2003 movie is only alluded to, at the very end.)

The whole thing is also hampered by its almost laughably dire tone.

Jaa acquits himself in the action scenes. However, his lack of any discernible acting "chops" might not be as noticeable if he weren't upstaged in that regard by Natdanai Kongthong, who plays the younger version of Tien.

Kongthong at least has some range. He's also quite good in the combat scenes (a sequence in which his version of the character fights a crocodile is among the film's best).

"Ong Bak 2" is rated R and features strong violent content and imagery (arrow fire, swordplay, hand-to-hand combat, stabbings, slashings, violence against animals, violence against women, and child-in-peril elements), graphic gore and blood, derogatory language and slurs, use of crude slang and other suggestive terms, brief drug content (opium smoking) and scattered mild profanity). Running time: 98 minutes.

e-mail: jeff@desnews.com