‘The Dark Knight’: Ledgerdemain, By Kurt Loder

A gifted actor goes out in a fireball of glory.

There’s an electrifying moment early on in “The Dark Knight” that involves a demented villain, a troublesome thug and an everyday writing device. It’s over in an instant — a passing jolt — but from that point on, the Joker , as alarmingly incarnated by the late Heath Ledger, has our undivided attention.

This is a considerable feat, given how crowded the movie is with Other Stuff: a love triangle, a second supervillain (third, if you count the brief encore by Cillian Murphy’s Scarecrow — out on a day pass from Arkham Asylum, presumably), angry mobsters, doomed clowns, an intricate financial rip-off, a side trip to Hong Kong, and, of course, wall-to-wall, floor-to-ceiling, sea-to-shining-sea pyro-automotive mayhem.

“The Dark Knight” is even more blazingly ambitious than its predecessor, the 2005 “Batman Begins.” Director Christopher Nolan lingers over roaring flames and flying rubble as if he had only lately discovered them. (Maybe he figured they’d seem fresh down at the tender end of the movie’s target demographic.) The rest of the picture is briskly edited, but Nolan’s delight in nonstop detonation helps push it up to the two-and-a-half-hour mark, and then over it. Fortunately, whenever the Joker appears, with his crumbling pancaked face, seaweed hair and giddy malevolence, things start perking up.

As the movie begins, Batman (Christian Bale) is in ill repute among the citizens of Gotham, who now revile him as an out-of-control vigilante. Meanwhile, the municipal criminal element, led by Salvatore Maroni (Eric Roberts, an even less-likely Italian mob boss than Tom Wilkinson was in the last picture), has problems of its own: Somebody has hoovered millions in ill-gotten gains out of the syndicate’s secret bank accounts. Then there’s the crusading new district attorney, Harvey Dent (Aaron Eckhart), a straight arrow who’s just as committed to thug-busting as Batman is, but equally opposed to the hooded crime-fighter’s corner-cutting butt-kickery. Batman, for his part, welcomes Dent’s arrival on the scene — what with all the burgher bad-mouthing lately, he’s seriously considering retirement. On the other hand, Bruce Wayne, the man hidden beneath those bat ears, can’t help noticing that Harvey is also making moves on the girl of his dreams, Assistant DA Rachel Dawes (Maggie Gyllenhaal in for Katie Holmes, thank you, God).

The would-be mastermind who’s ripping off the mob is a rogue mogul named Lau (Chin Han), who’s inconveniently located in Hong Kong. Batman and the Joker both want this guy (the mobsters, idiots all, think the Joker is working for them); but it’s Batman who goes the extra 10,000 miles to make the collar. Was this trip worth the sizable chunk of production budget it undoubtedly cost? Maybe. There’s a glorious shot of the globetrotting superhero perched high above the gleaming city, and when he dives down into the night and his cape-wings snap open and he begins sailing around among the skyscrapers, you have to smile at the simple beauty of the image. Then, following a ferocious bullet ballet at Lau’s corporate headquarters, there’s a spectacular airborne getaway that justifies whatever amount it cost to stage.

In fact, few directors can whip up action with as much mad gusto as Nolan. His set-piece 18-wheeler truck somersault, already familiar from the trailer, may be a first; but the smaller-scaled shot in which Batman guns his armored motorcycle (OK, “Bat-Pod”) halfway up a wall and flips it to reverse his direction is pretty slick, too. I won’t go into the very long chase scene through Chicago’s multilevel streets — a riot of careening trucks, plummeting helicopters and thundering bazookas — except to say that it’s a virtuoso demonstration of choreographed pandemonium.

Amid all this photogenic chaos, however, the story of Harvey Dent — one of the more complex characters in the Batman universe — feels oddly truncated. As anyone who’s likely to see “The Dark Knight” will probably know, Dent suffers a gruesome injury that leaves half of his face looking like something you might find hanging from a hook in a meat locker. It also cleaves his personality, turning him into the tragically conflicted Two-Face, a semi-villain who determines his every significant action — for good or for evil — with an amoral flip of a coin. Aaron Eckhart’s heroic jaw and beaming blondness make for an appealing pre-disaster Dent, and he navigates the character’s slide into madness with careful emotional shifts. But in the comics, Two-Face, who’s been around almost from the beginning, keeps coming back to inflict further worry on his costumed adversary (in fact, he’s still around today). In this re-tooled film franchise, however … well, let’s say that probably won’t be happening.

As in the first movie, Bale does his most personable work as Bruce Wayne. Bantering with his suave armorer, Lucius Fox (Morgan Freeman), and his loyal butler, Alfred (Michael Caine), or languidly disporting himself on a yacht filled with twittering ballerinas, Bale the actor seems actually to be having the fun that the troubled Wayne character can only pretend to. Once he slips into Batman’s cape and cowl and trademark glower, though, he’s boxed in; and the choked, staccato growl with which he voices his lines seems weirder than ever — he sounds as if he’s speaking from the bottom of a frog pond.

This allows Ledger to take over the movie — which he probably would have done in any event. His performance as the Joker glimmers with unexpected tones and edges, and it lightens the movie’s thick, operatic texture. The character as written has an odd flaw: Although he’s supposed to be an improvisational maniac (“Do I look like a man with a plan?”), his murderous schemes — especially one involving two ferries filled with terrified passengers — are in fact intricately worked out in advance. But Ledger plays him as a wild card anyway, and he’s scary and funny and completely convincing. Whatever the movie’s shortcomings (an attempt to raise FISA-style objections to an altogether nifty eavesdropping stunt is pretty lame), Ledger barrels past them. Eerily, at the end of this film, his Joker seems to have been set up for a return engagement in the next one. “I think you and I will be doing this forever,” he tells Batman. If only.

Check out everything we’ve got on “The Dark Knight.”

For breaking news, celebrity columns, humor and more — updated around the clock — visit MTVMoviesBlog.com.

Don’t miss Kurt Loder’s review of “Mamma Mia!,” also new in theaters this week.