From 1979-1981, the popular hiking trails of Northern California became the setting of a terrifying mystery. A man known as the Trailside Killer was raping and killing women in a place they had always felt safe. The cold-blooded attacks stunned the community and frustrated law enforcement. They had few clues as to the killer's identity, until one victim managed to get away and identified a middle-aged man living an ordinary life with his parents.