Michelle reflects on the 1984 murder of her childhood neighbour Kathy Lombardo, which she credits with planting the seed for her lifelong fascination with unsolved crimes. The EAR serial predator escalates from attacking young women to targeting couples.

In 1979, law enforcement is thrilled when the EAR attacks abruptly stop in Northern California, but in reality, the still unknown assailant has moved south to commit a number of gruesome murders in the Santa Barbara area, known as the "Original Night Stalker" series.

After gaining access to a treasure trove of case files, overwhelmed by the amount of material and the graphic nature of the crimes she is investigating, Michelle struggles to balance the demands of her self-described addiction to her work with her family life.

As Michelle's loved ones cope with her sudden death, her work to unmask the Golden State Killer lives on. Inheriting Michelle's 37 boxes of case files, researcher Paul Haynes and true crime writer Billy Jensen work alongside Michelle's husband to finish her book.

As a 72-year-old former police officer's arrest unfolds in real time, chilling facts materialise that illuminate Michelle's prescience in her book's epilogue, "Letter to an Old Man".

The victims of the Golden State Killer seek closure following the recent sentencing.