Amy Ryan gives the performance of her career as a mother on a mission in Netflix’s Lost Girls. Based on Robert Kolker’s 2013 nonfiction bestseller of the same name, Lost Girls is the true story of the Long Island serial killer, who was thought to have murdered ten to 16 people, mostly women associated with sex work. One of those women was believed to have been Shannan Gilbert. When Shannan goes missing, her mother, Mari Gilbert (Ryan), will stop at nothing to find out what happened to her, and what ensues is a story of police neglect in Suffolk County where four of the bodies were found. Lost Girls isn’t a mystery; we’re told from the beginning that the murders remain unsolved. The challenge is to make the viewer care despite knowing how it will end. Director Liz Garbus—in her narrative feature debut— rises to this challenge by taking the viewer deep into the complicated life of the Gilbert family, both fiercely loving and dysfunctional, and showing the flaws in a law enforcement system where some victims are deemed worthy and others are not.