February 1987. Ron and Margie Pandos awake to find their 15-year-old daughter, Jennifer, missing, with a strange handwritten note as their only clue. Decades later, Jennifer's brother Stephen reopens the investigation, convinced his parents are behind her disappearance.

While Margie is offered immunity in exchange for answers, investigators scrutinize Ron's past as a Vietnam veteran and his criminal record. After decades of estrangement, Stephen confronts his father and makes a desperate plea for the truth. Later, new evidence steers the investigation in an unexpected direction.

While a newly discovered trove of Jennifer's writing sheds light on the teen's struggles, new leads refocus the investigation. Certain that his mother holds the key to finding answers, Stephen continues to press Margie.

As the investigation ramps back up, Stephen learns about secret legal proceedings and emerging persons of interest. As more information comes to light, the investigation continues to take an emotional toll on Stephen and his family.