Heads up: a thunderbolt is about to rip into the blanket of bland we call summer movies. The Dark Knight, director Christopher Nolan's absolute stunner of a follow-up to 2005's Batman Begins, is a potent provocation decked out as a comic-book movie. Feverish action? Check. Dazzling spectacle? Check. Devilish fun? Check. But Nolan is just warming up. There's something raw and elemental at work in this artfully imagined universe. Striking out from his Batman origin story, Nolan cuts through to a deeper dimension. Huh? Wha? How can a conflicted guy in a bat suit and a villain with a cracked, painted-on clown smile speak to the essentials of the human condition? Just hang on for a shock to the system. The Dark Knight creates a place where good and evil — expected to do battle — decide instead to get it on and dance. "I don't want to kill you," Heath Ledger's psycho Joker tells Christian Bale's stalwart Batman. "You complete me." Don't buy the tease. He means it.

The trouble is that Batman, a.k.a. playboy Bruce Wayne, has had it up to here with being the white knight. He's pissed that the public sees him as a vigilante. He'll leave the hero stuff to district attorney Harvey Dent (Aaron Eckhart) and stop the DA from moving in on Rachel Dawes (feisty Maggie Gyllenhaal, in for sweetie Katie Holmes), the lady love who is Batman's only hope for a normal life.

Everything gleams like sin in Gotham City (cinematographer Wally Pfister shot on location in Chicago, bringing a gritty reality to a cartoon fantasy). And the bad guys seem jazzed by their evildoing. Take the Joker, who treats a stunningly staged bank robbery like his private video game with accomplices in Joker masks, blood spurting and only one winner. Nolan shot this sequence, and three others, for the IMAX screen and with a finesse for choreographing action that rivals Michael Mann's Heat. But it's what's going on inside the Bathead that pulls us in. Bale is electrifying as a fallibly human crusader at war with his own conscience.