“Wild child” movies are pretty much a cinematic staple–from serious pieces like Tuffaut’s 1970 film of that name and Werner Herzog’s “The Enigma of Kaspar Hauser” to the endless run of “Tarzan” movies and exploitation drek like 1987’s “Wild Thing” (written by John Sayles, of all people). But as far as I know, no one before now has thought of adding to the mix as strong dose of “Fight Club.” That’s the bright idea behind “Unleashed” (aka “Danny the Dog”), a brainchild of Luc Besson, the French writer-director who’s become a sort of Gallic Larry Cohen, the continental purveyor of high-concept schlock. In the scenario Besson has fashioned, Danny (Jet Li) is the attack dog for a ruthless Glasgow loan shark named Bart (Bob Hoskins). He’s been raised like an animal since youth, kept in a cage and trained to be something akin to a human put bull, who mindlessly attacks his master’s non-paying customers whenever Bart removes the collar from around his neck and simply whispers, “Get ’em.” Bart also moves to increase his income by having Danny participate in to-the-death hard-man competitions, a metier in which he excels. The plot kicks in when Bart and his associated henchmen are injured, perhaps fatally, and Danny finds his way into the home of Sam (Morgan Freeman), a blind piano-tuner who’s tapped into the inarticulate fellow’s inchoate love of music (which once again, to use the common misquotation, soothes the savage beast), and his effervescent piano-student stepdaughter Victoria (Kerry Condon); they embrace the child-man and begin drawing him into the human world of relationships and pleasures. This idyll can’t last, of course, and soon Bart and his gang are back, determined to drag the now-enlightened and humanistic Danny back into the world of crime and violence and threatening his new family in the process. Danny’s recollections of his real childhood under Sam’s kindly tutelage also reveal the terrible truth about how he came to be Bart’s pet. The volatile mixture leads to a typically over-the-top finale in which many kicks and punches are exchanged by innumerable combatants and great quantities of blood are spilled.

The strange thing about “Unleashed” is how it mingles a thoroughly ridiculous action movie with an incredibly mawkish melodrama. On the one hand, the essential premise of training a man through some unexplained Pavlovian methodology into an automatic enforcer is absurd (the reason, one presumes, why Besson never attempts to show us how it was done), but even if you accept the idea, it’s not worked out with any great plausibility. If Danny is so notoriously effective in extracting cash from debtors, for example, why is it that Bart seems to find it necessary to have him attack virtually every one of his customers? Haven’t they any inkling about how the consequences of non-payment? And isn’t Bart smart enough, since he’s hatched this entire scheme, to know that once his secret is out, it’s unwise to bring Danny before his clients with the collar still on, so that they can outwit him simply by preventing the collar from being removed? And why doesn’t somebody just shoot Danny while he’s still kept placid by the collar? Quite frankly, the stupidity of the whole underlying plot foundation is astounding. Still, that side of the movie at least offers the opportunity for the sort of fast, brutal action that Jet Li fans will eat up, and the star proves as agile and dextrous as can be; Hoskins, meanwhile, gets the opportunity to return to the sort of nasty thuggishness that made his career back in 1980 in “The Long Good Friday”–this time with an even higher degree of venom that borders on (maybe passes into) self-parody. The other half of the picture, on the other hand, is so rankly sentimental and phonily poetic that in many respects it’s more risible than the action side. (One lesson Sam teaches Danny is how to gauge a melon’s ripeness by tapping on it with one’s finger. It’s a lesson that’s especially acute, because this part of the movie is definitely overripe.) Jet Li’s thespian limitations become painfully apparent here, and even as accomplished a performer as Freeman has trouble making the figure of a saintly blind piano tuner remotely convincing. (Condon, on the other hand, is the same sort of lightweight nonentity that Besson has utilized in many of his other pictures. And her playing is ludicrously amateurish for somebody who’s presented as a prize-winning advanced keyboard student; the Mozart we hear at the close is played at about quarter-speed.) Both parts of “Unleashed” share one thing, though: an excess of exterior virtuosity. Though Besson didn’t direct it himself–it’s the work of Louis Leterrier, who also helmed the wildly flamboyant “The Transporter” for him–it has all his trademarks: an extravagantly, unnecessarily flashy visual style, marked by cinematography (by Pierre Morel) that emphasizes the shimmering browns and reds in Jacques Bufnoir’s production design and keeps the camera swooping about in the most pointlessly athletic ways (endlessly sweeping through hallways and stairwells and, at one point, even passing through the innards of a piano). The result is a sleek surface that can briefly, but only briefly, camouflage the vacuity of what’s beneath it.

It has to be admitted that “Unleashed” isn’t exactly boring, even during embarrassing moments like “See Danny Eat Ice Cream for the First Time.” But it is brainless pulp whose mixture of high-octane physicality and blubbering bathos never really gels.