Sierra Barter investigates her step-grandfather. She reaches out to Jim’s ex-wives, children, and stepchildren, and assembles a horrifying image of the man her step-grandfather was and the terror he inflicted on his own family.

To most, Jim Mordecai was a revered teacher, but to others he was a monster. Sierra questions if Jim’s crimes escalated, and a family heirloom sends her down a rabbit hole where a series of unsolved murders has her asking if Jim could be the killer.

Sierra’s uncle implicates Jim with a disturbing story, and a private investigator urges Sierra to find evidence. Searching through family storage, Sierra learns the truth about a night that changed her family forever, and her investigation pivots.

With the help of cutting-edge technology, Sierra can build a DNA profile of Jim. Armed with the evidence she needs, Sierra hands her files to law enforcement, hoping to convince them to investigate, and help her family step out of Jim’s shadow.