There's a beautiful high-angle shot, early in The Dark Knight , that looks down on Bruce Wayne (Christian Bale) in full Batman regalia as he perches atop a Gotham skyscraper, surveying the city he lives to protect, then leaping off and spreading his majestic bat wings to swoop down into the night. Bruce's trajectory is also the film's. It traces a descent into moral anarchy, and each of its major characters will hit bottom. Some will never recover, broken by the touch of evil or by finding it, like a fatal infection, in themselves.
The Dark Knight ,...