The purpose of the cipher is concealment. David Fincher’s new film Zodiac demonstrates this in cinematic terms.

It’s a brave director who returns after an extended absence from cinema and then subverts the very film that made his career. But that is exactly what Fincher has done with Zodiac. Where his first masterpiece, Seven, was a frenetic, angry take on the serial killer film with a uniquely urban aesthetic, his new film is almost the polar opposite. Though the acute, almost obsessive, attention to detail flows from one scene to the next, it’s the subtle, low-key aspects of the filmmaking that shows it for what it is: a filmmaker maturing before our eyes.

Where Seven had an energetic young pup Detective Brad Pitt, Zodiac’s centre is the introverted Robert Graysmith (played here with wide-eyed fervor by Jake Gyllenhaal), a political cartoonist on the San Francisco Chronicle who befriends crime beat reporter Paul Avery (Robert Downey Jr., beautifully channeling a foppish Doctor Who) while building an obsession with the very real Zodiac case from the 1970s that has stumped lead investigator Inspector Dave Toschi (the compelling Mark Ruffalo).

The technician in Fincher is still vibrantly alive in the powerful time lapse photography showing the construction of the Transamerica Pyramid and the digital mapping of the Zodiac’s letters to the Chronicle onto the audience’s perspective, but these are parts of the puzzle conceit. Time moves on, blocks fall perfectly into place elsewhere, but the worlds of Graysmith, Avery, and Toschi are separate, crumbling into the same ciphers they are meticulously working to solve.

Their lives have become as muted, and as sickly, as the jaundiced colours of Harris Savide’s potent cinematography; lives wound up dangerously tight, yet adrift in the cruel wide spread of San Francisco Bay and the open plan offices of the Chronicle that recall Pakula’s All The President’s Men, and enveloped in a menacing soundscape of shrilling telephones, pounding machinery, and departing planes. Even nature is adulterated in the sunlit lakeside setting of the most horrifying scene in the film that also contrasts nicely with the enveloping darkness of Seven’s more gruesome moments.

This is a work that requires the utmost concentration and patience on the part of the audience. Just as he did with Seven, The Game and even Fight Club, Fincher confronts us with a conundrum, but in this case one that has no solution. In lesser hands, with less restraint, a more bowdlerized ending would be the result, but instead Fincher leaves us on a chilling note of success just out of reach. It’s dark and pessimistic, but just as Graysmith stares into the face of evil and lives, so do we, but changed by both a fine tribute to the paranoia films of the 1970s and a perfect example of growth in a filmmaker.