A documentary filmmaker sets out to tell the story of the biggest serial killer case in California history and uncovers a terrifying tale that begins with the disappearance of Paul Cosner.

With the discovery of Leonard Lake's cabin, investigators find the hidden cell where Lake kept his victims; they also unearth Lake's recorded manifesto, which details his depraved plans for Operation Miranda.

An international manhunt ensues when Leonard Lake's accomplice, Charles Ng, flees the country; the victims' families, including Paul Cosner's sister, fight to bring Ng to justice and answer for the crimes he committed with Lake.