Lois and David Riess live a seemingly normal life as parents to three children, several grandchildren, and a thriving business in Blooming Prairie, Minnesota, until, one day, David's dead body is discovered and Lois goes on the run. As Lois, now in prison, recounts her childhood and upbringing, a disturbing psychological portrait emerges of a woman battling many emotional demons. However, Lois's methodical behavior after the murder may show the work of a calculated killer when another body is discovered.

After the discovery of Pamela Hutchinson's body in Florida, a nationwide manhunt for the "Killer Grandma" begins and two weeks later, witnesses recognize Lois in Texas. Appearing placid and cooperative, Lois claims not to remember many details of her crime spree, but police have evidence that details her sinister plan.