It all starts simply enough: “My name is Domino Harvey. I am a bounty hunter,” snarls a female Briton. The viewer is fortunate to be sure of those two clear facts, because for the next two hours, one cannot be sure of too much else.

Most audience members will probably walk out of Tony Scott’s “Domino” without the slightest clue as to what, exactly, a bounty hunter does — despite the fact that the movie is about a team of bounty hunters, and despite the fact that it is narrated from start to finish by a bounty hunter. Yes, the audience sees Keira Knightley assaulting and cuffing bad guys in the title role, often beneath gaudy aviators and a bulky bulletproof vest. Yes, the characters throw around plenty of industry slang to show off their authenticity. And yes, the weaponry includes submachine guns, throwing knives, nunchucks and number two pencils.

But then there is also an Afghani freedom fighter, a severed arm, a mob boss, plenty of cigarettes, plenty of tattoos, a few hallucinogenic drugs and one live set of Jerry Springer. “Domino” hurls so much at the viewer so quickly — usually through frenetic, hyperactive editing techniques — that it neglects to provide an education in the most basic elements of its plot. The audience is up in the air before they know it, lost in a flurry of plot twists and visual gimmickry.

Based, “sort of” (per the opening credits), on the life of Domino Harvey, daughter of famous screen actor Laurence Harvey, the film would appear to be endowed with ample and fascinating subject matter. After all, how did a wealthy young girl from the English upper crust end up as a bounty hunter in southern California? Clearly there is more to it than a Eurotrash make-over.

Instead of providing an explanation by examining Domino’s character in detail, the movie contents itself with answers as rushed and simplistic as could be possible. After the death of her father, Domino is sent to a boarding school at a young age, where her pet goldfish soon dies. The result? Domino vows never to invest herself emotionally in anything ever again. Instead, she develops a nasty curl in her upper lip.

From childhood, the film progresses straight to Domino’s college days, where the metamorphosis is already complete. “I hated everyone and everything,” she says in her narrative. Thirty minutes into the film, any psychological heavy lifting is over with. Domino begins her life as a bounty hunter, and from this point of departure the audience is sent careening into a loud and busy plotline.

Domino’s work takes her through a veritable labyrinth, alternating between the bright existence of Beverly Hills and a dingy criminal underworld dripping with machismo. Scott might have relied on his audience to draw the contrast for themselves, but Domino is insistent on driving the point home: “This ain’t Sunset Boulevard.”

Her partners, Ed (Mickey Rourke) and Choco (Edgar Ramirez), are ex-cons cut from the same cloth as many of the criminals they take down. All three main characters are portrayed with as much grace and subtlety as Richard Kelly’s hectic script will allow, but they are constantly bumped aside by an endless (and needless) parade of minor players. Knightley, Rourke and Ramirez do a commendable job of lending three-dimensionality to roles that might otherwise become caricatures, but just when the viewer tries to peel back another layer, a different character bustles into the mix.

Indeed, the web of interconnected people and situations grows so ornate that one feels like giving up just when the movie ought to be building towards a climax. The final half-hour is a miasma of violence, drugs and more violence as Domino and her team become embroiled in an ill-fated and ill-explained caper involving $10 million and an armored car. It is as if the makers of “Domino” could not think of a chain of events that would not be cliche, so they decided to make it horribly confusing instead.

“Domino” has turns where it can be immensely refreshing — Mo’nique and Christopher Walken each submit lively appearances — but by and large the film is too clumsy to support its own weight or the audience’s attention for long. The final line is more telling a commentary than might have been intended: “There is only one conclusion to every story: we all fall down.” It certainly does not take long for “Domino” to fall, and fall hard.