Between December 1968 and October 1969, the person who called himself the Zodiac was linked to five confirmed murders and two attempted murders in Northern California. What made the case grow beyond the crime scenes was the communication system around it: phone calls, letters to newspapers, threats, symbols, and ciphers that turned the press and public into part of the investigation. This episode follows the confirmed attacks, the newspaper letters, the Z408 and Z340 cipher solutions, the unresolved Z13 and Z32 puzzles, and the careful line between documented evidence and decades of suspect speculation.