It begins with a whimper; a pair of lovers on a lonely road shot point-blank in the dead of night. A month later the killer sends a series of ciphers to the San Francisco Chronicle and Examiner and demands that they be published. If not he promises to continue his murderous rampage, which he does anyway: brutally stabbing a young couple enjoying the scenery at an isolated lake in the wine country. As bloody incidents mount, the pressure in the newsroom escalates. Colorful Chron crime reporter Paul Avery (Robert Downey Jr.) is the first to fall under Zodiac's spell, followed by mild-mannered newspaper cartoonist Robert Graysmith (Jake Gyllenhaal) and SFPD homicide Inspector David Toschi (Mark Ruffalo).
Zodiac continues to taunt the press and police while Avery, Graysmith and Toschi agonize over hot clues gone cold and concurrences whose dots never quite connect. The trio is consumed by the psychological warfare Zodiac is waging on a horrified public.
The trail eventually leads to a burly loner with a sketchy alibi (the marvelous John Carroll Lynch) and, in one of the film's scarier set pieces, a creepy movie enthusiast living over a "Silence of the Lambs"-like basement.
As the narrative draws out over a decade of dead ends (and a hefty two-and-a-half-hour running time) Fincher deftly sustains an even keel of suspense, maintaining a methodical rhythm of fear and anxiety.
The chilling cat-and-mouse game takes its toll; Avery descends into a vortex of drugs and disenchantment and the intrepid Graysmith loses his wife and kids to a singular obsession with finishing a book chronicling the unsolved case (on which this film is based).
The parade of famous faces is unusually impressive; seems everyone wanted in. Brian Cox (as celeb attorney Melvin Belli), Dermot Mulroney, Chloe Sevigny, Philip Baker Hall, etc. San Francisco circa the '60s and '70s is scrupulously recreated with an eye to workaday reality, not a bell-bottom or burning bra in sight.
The violence may be difficult for some but it's perfectly in keeping with Fincher's artistic vision. "Zodiac" is smart and substantial, the kind of project sorely lacking on the current cinematic landscape. One or two brief narrative lulls are all that keep "Zodiac" from masterpiece status.
Fincher is back, and he's better than ever.