Here is the ugly truth nobody at Warner Bros. can possibly utter aloud: The death of Heath Ledger will be good for The Dark Knight’s bottom line. Make no mistake, the movie was going to be huge anyway; 2005’s Batman Begins didn’t exactly under-perform at the box office. But plenty of potential ticket-buyers will be driven either by morbid curiosity or perhaps a desire to—for lack of a better term—pay their respects. Villain performances often give comic-book movies much of their kick even without the addition of real-life tragedy, and for the last few months it has been excruciatingly clear that whatever Ledger did with The Joker, he was going to suck every last drop of publicity oxygen out of the room.

And that’s a damned shame—not because Ledger doesn’t deliver a terrific performance, but Christopher Nolan’s movie deserves more than the unspoken subtitle Featuring Heath Ledger’s Last Completed Performance. As much as any of Nolan’s films, The Dark Knight uses genre packaging to deliver a brilliantly knotty tangle of philosophical questions. It’s a film that insinuates itself into your backbrain, and not just because of the leering guy in the smeary makeup.

That guy jumps into the narrative from the outset, as The Joker engineers the theft of millions from a mob bank. He’s out to grab the attention of organized crime bosses, because he has a proposition: He wants to be hired to kill that caped thorn in their collective sides, Batman (Christian Bale). With Bruce Wayne’s alter-ego doing vigilante night-watch duty and crusading new district attorney Harvey Dent (Aaron Eckhart) handling the law-and-order side, it’s not a great time to be a criminal in Gotham. It is, however, a delightful time to be a gleeful anarchist who wants to show how easy it is to exploit society’s darkest fears once things get a little dicey.

Nolan brings back plenty of familiar pieces from Batman Begins: Batman’s police force contact Jim Gordon (Gary Oldman); Wayne Industries technical guru Lucius Fox (Morgan Freeman); faithful manservant Alfred (Michael Caine); and Bruce Wayne’s former flame Rachel Dawes (Maggie Gyllenhaal, replacing Katie Holmes). More significantly, Nolan and co-scripter David S. Goyer bring back the sensibility that energized Batman Begins. As sharply as Nolan crafts action sequences—including a knockout sub-street-level car chase—he’s not interested in churning out easy-to-consume summer fare. Even for the era of the brooding superhero, The Dark Knight never feels like it cares if a single pre-teen whoops in delight. It’s fan-boy entertainment for fan-men and fan-women.

More specifically, it’s an of-the-moment meditation on the tissue-thin membrane between civilized morality and terror-driven morality of convenience. Nolan wrestles with Batman as both a force for good and a symbol of a broken system; he pokes at the potential for abusing high-tech surveillance, even for a good reason. He even turns the film’s climax into a horrifying test of the kind of ethics-class hypotheticals that ask whom we’d throw out of the lifeboat first. The Joker becomes a manifestation of the principle that we’re all shades-of-grey creatures; he lives to prove that where every rule is in some way arbitrary, the complete absence of rules makes a perversely logical sense.

It’s left to Heath Ledger to find the center of The Joker’s anarchic drive—and he does so, perhaps fittingly, by having The Joker re-create his own history and psychology however it suits him in the moment. In a performance orders of magnitude creepier than Jack Nicholson’s showy collection of ad-libbed craziness in the 1989 Batman, Ledger slithers his tongue around The Joker’s scar-crossed smile—not like a madman, but like a Biblical serpent tempting humanity back to some primal state. All that, and he somehow pulls off looking menacing while rocking a nurse’s uniform.

In such a complex exploration of chaos, it’s either appropriate or ironic that The Dark Knight at times feels too densely plotted. The first 60 of the film’s formidable 152 minutes are spent mostly building up to Nolan’s thematic content, and the various sub-plots—including a potentially intriguing but tossed-aside bit about copycat Batmen—fight for time to make an impact. But when Nolan does pull all the pieces together, The Dark Knight becomes a rich psychological drama only incidentally about a guy in a cowl. Ledger’s final performance is part of a grand, unsettling work of pop art. And only a part.

THE DARK KNIGHT

***1/2 (three and a half out of four stars)

Starring: Christian Bale, Heath Ledger, Aaron Eckhart

Directed by Christopher Nolan

Rated PG-13.