In the early morning hours of December 31, 1999, 10-year-old Krystal Surles and her friend Kaylene Harris, 13, were brutally attacked by a knife-wielding intruder, who slashed their throats. Kaylene died, but Krystal walked to a neighbor's house for help, and survived. Despite her injuries, she helped police identify the killer. Two days after the crime, police arrested a 35-year-old drifter named Tommy Lynn Sells. During questioning, Sells told police that he had committed dozens of murders over the past 20 years. An eighth-grade dropout who often made money as a carnie, he said he had committed his first murder in Hollywood, Calif., in a street fight. Sells said that he had killed people all over the country, from California to West Virginia. Harold Dow reports on a man who for 20 years got away with murder in a big way and the child whose courage put an end to the killings.