The true story of the investigation of the "Zodiac Killer", a serial killer who terrified the San Francisco Bay Area, taunting police with his ciphers and letters. The case becomes an obsession for three men as their lives and careers are built and destroyed by the endless trail of clues.
Sarah returns with her father and uncle to fix up the family's longtime summerhouse after it was violated by squatters in the off-season. As they work in the dark, Sarah begins to hear sounds from within the walls of the boarded-up building. Although she barely remembers the place, Sarah senses the past may still haunt the home.