After a series of violent, shocking murders, detectives and journalists are taunted by a killer's riddles and coded messages, demanding they be printed in the paper or face more murders. The race is on to hunt his true identity.
Detectives realize that a string of murders that predate the spree claimed by Zodiac appear to be connected and turn to them in hopes of finding clues in the investigation, perhaps also linking them to the #1 suspect, Arthur Leigh Allen.
A hoard of handwritten letters, kept in secret for decades, is revealed and offers a never-before-seen window into Allen's mindset and, more shockingly, incriminating details, which finally force the family to confront their suspicions.
