In 1999, three women went missing in Yosemite National Park, launching the largest search and rescue operation in US history.  The bodies of two of the women are found in a burned car, and the third is only found when the killer sends a taunting note to the FBI.  Five months later, when a fourth woman is found beheaded near the park, the Bureau believes a serial killer may be on the loose.

After a "family friend" murders a California mother and her 8-year-old son, the woman's 16-year-old daughter is nowhere to be found. Authorities learn the killer has kidnapped Hannah Anderson and taken her to the remote wilderness of Idaho. The FBI's Hostage Rescue Team receives a tip and tries to track down the pair before it's too late.