Plot It’s 1969, and the San Francisco Chronicle receives letters from serial killer ‘Zodiac? Reporter Paul Avery (Downey Jr.) covers the case, frustrating cops David Toschi (Ruffalo) and Bill Armstrong (Edwards). Years pass, until only Chronicle cartoonist Robert Graysmith (Gyllenhaal) is still in pursuit.Verdict You’ll need patience with the film’s approach, which follows its main characters by poring over details, and be prepared to put up with a couple of rote family arguments and weary cop conversations, but this gripping character study becomes more agonisingly suspenseful as it gets closer to an answer that can’t be confirmed.