On December 20, 1968, as a small Northern California town prepares for the Christmas holidays, a teenage couple is viciously murdered at a desolate lover's lane, sending a shock wave of horror through the town of Vallejo. Investigator Matt Parish of the Vellejo Police Department, husband to Laura and father to twelve-year-old son Johnny, is assigned to the investigation. With very few leads to go on, and demands to solve the crime quickly, the pressure mounts when a renegade local reporter sensationalizes the tragedy. Weeks turn into months as the grueling case continues with no concrete evidence to expose the identity of the killer. At home, Parish must come to terms with the dramatic emotional effects the horrible murders and the failing investigation have brought on his family. On July 4, 1969, the killer strikes again. Amidst the festive summer holiday, a young couple is gunned down at close range in a dark parking lot. Again, the attacks show no indication of robbery or sexual molestation. Then, the unthinkable happens. A shocking phone call to the police is made within an hour of the attack, a man confessing to the murders of the two couples. Next, a letter is received at the local Vallejo paper, as well as the San Francisco Chronicle and the San Francisco Examiner, threatening a dozen more murders that weekend unless the letter is printed. Included in the letter is a cryptogram, which according to the killer, if deciphered, would reveal his identity. Parish descends into the all-consuming complexity of the case: codes, ciphers, composite sketches, psychological profiles and astrological patterns. His desperate obsession, fueled by the increasing media coverage, sends his family to the edge. After more taunting letters, phone calls, and another savage and bizarre double murder of a young couple in broad daylight, Parish believes he has finally identified a suspect. Disobeying orders, Parish storms the suspect's house only to discover that his investigations have led him to a man unconnected to the crimes. Soon after the police learn the horrifying news that the Zodiac has killed again. On April 24, 1978 the San Francisco Chronicle receives another letter asking, "Who will make a movie about me…?" and the chilling statement, "I'm now in control of all things."
