In September 1991, a young mother in Arlington, Texas, Cynthia Gonzalez, left for a late-night appointment and never came home. Her car was found 40 miles away, and the investigation that followed would consume a legendary detective's career through serial killer suspects, failed polygraphs, and confessions that went nowhere. Thirty-four years later, a college classroom full of students at the University of Texas at Arlington, who weren't even born when she was killed, would find what everyone else missed.