This two-part true-crime documentary takes viewers back in time, dusting off case files from nearly 40 years ago. It follows two women, detective Jackie Nichols and Gloria Bobertz, as they work to unravel mysterious disappearances that tormented the small Lewis Clark Valley area along the Washington and Idaho border in the 1980s. Five youngsters vanished, and to this day only three bodies have been found. The other disappearances remained unsolved. While local police worked for years to find the culprit, the cases were shelved due to minimal evidence and leads. Now Nichols and Bobertz, the cousin of one of the victims, track down old witnesses and pursue new leads. The most chilling part of these cases? Investigators are certain who the killer is, but no one has been able to gather enough evidence to confidently prosecute him.