Dave, I want a gun.

Zodiac begins with a familiar scenario: a young couple parked in a secluded spot get the heebie-jeebies when they recognize a car that has been following them (the car takes the role usually occupied by a strange noise). The outcome of the scene is unsurprising, but our anticipation of violence creates immediate tension, which director David Fincher sustains with subtletly, reducing the scene to its barest visual and narrative elements, creating a moment of stark horror. Donovan's haunting "The Hurdy-Gurdy Man" joins the deafening noise of gunfire on the soundtrack as we are introduced to the titular killer ("the roly-poly man"), a villain without a face, permanently cloaked in shadow; the scene at once appeals to and subverts our expectations for the film, a meticulously crafted variation on the police procedural subgenre. Zodiac is deeply, persistently creepy in a way that few films are, obsessed as it is with our primal, deep-seated fear of unsolved mysteries and, by extension, the unknown - it's a film that deserves mention next to such masterpieces of paranoia as The Conversation and Blow Out.

The film follows the search for the Zodiac killer from the perspective of three men - San Fransisco Chronicle columnist Paul Avery (Robert Downey Jr.), detective Dave Toschi (Mark Ruffalo) and Robert Graysmith (Jake Gyllenhaal), a cartoonist for the Chronicle who ultimately wrote a book about the Zodiac that is the basis for the film's screenplay. The film's narrative spans years, then decades, chronicling all the clues, dead ends and unanswered questions accompanying the case. The first half of the film recreates the Zodiac's crimes in unflinching detail, captured in razor-sharp HD by cinematographer Harris Savides (who also shot Gus Van Sant's Elephant, a spiritual cousin to Fincher's film), and documents his years-long correspondence to the Chronicle and the SFPD, taunting their inability to uncover his identity. But as the years pass and film progresses, the Zodiac's crimes stop and his contact with his pursuers trails off - the killer is a disembodied spectre hanging over the film, and the true villain is not any of the suspects we meet but rather the aimless, dislocated feeling of dread stemming from the lack of a pat resolution. A terrifying scene set in a possible culprit's home (Who Framed Roger Rabbit will never be the same) is undercut by the failure of the evidence to incriminate said suspect. The film teases our desire for an answer, fetishistically recreating in minute detail a newsroom straight out of All the President's Men and using its intrepid protagonists as archetypal figures in the search for truth. But Fincher is ultimately concerned with how this search consumes and destroys each man. A scene where Toschi criticizes Dirty Harry (loosely based on the case) for its fascistic wish fulfillment forces us to confront our own need for retribution, which, as Fincher subtly reminds us, is rarely the same as resolution.

Zodiac's ambiguities are mirrored in the film's narrative techniques, particularly the conflict between the film's digital medium and its rigidly analog narrative structure. Zodiac is a long film, but never a bloated one - the story unfolds at a quick pace, a barrage of facts loaded into every scene. Yet Fincher raises more questions than answers - for instance, he employs titles indicating the passage of time as Kubrick did in The Shining, using repetition to underline time as an abstract concept that we collectively employ to assign continuity to our lives. When we meet the prime suspect (John Caroll Lynch) during an interrogation, the camera remains at a distance, allowing us to read whatever we choose into his guarded mannerisms and halting, defensive speech. At one point, Graysmith tells his wife (Chloe Sevigny, underused in a standard worried wife role that is the film's only weak point) that he needs to look the Zodiac in the eye and know that it's him, yet the film uses images to challenge the idea that seeing is believing. Taking place at a moment in time when modes of information were rapidly expanding, Zodiac shows us everything but explains nothing; in a sense, is the perfect horror movie for empiricists.

The performances are stellar all around - Downey is characteristically brilliant as a hipster reporter whose seeming ironic detachment is a defensive measure against his very real fears, and Ruffalo is sympathetic as a good cop beaten by the weight of time. Gyllenhaal, who has publicly bitched about Fincher's demanding methods, is like the director's Shelley Duvall; he uses the actor's earnestness to create a progagonist with ambiguous motives. Graysmith devotes decades to the pursuit of the Zodiac, putting his family's safety at risk - while other characters frequently comment on his guilelessness, his goodness (and, consequently, his identity) is defined in relation to his elusive subject. Graysmith needs to know Zodiac in order to know himself; while Gyllenhaal isn't a great actor, he works brilliantly as a character who isn't quite there.

But the real star of the film is Fincher, for whom this film marks a major step forward. This is not a dismissal of his earlier films - Seven and Fight Club are brilliant and endlessly rewatchable, but they're didactic and relatively accessible, their strength residing in the sheer visceral impact of the images. With Zodiac, Fincher takes a more subtle, disciplined approach and reveals that, in addition to his technical gifts, he's also a great storyteller. When he allows for a visual flourish such as a time-lapse shot of the Transamerica Pyramid being built brick by brick, the images have a meditative, poetic quality that enhance the film in surprising ways. Zodiac may be the film that ends up defining Fincher - it's a masterpiece, sometimes terrifying, sometimes maddening, and competely spellbinding. In an interview, Downey compared Fincher to Kubrick; he's begun to live up to the comparison, so let's just hope that he's a bit more prolific - the world needs more films as insistently alive as Zodiac.