A DNA hit in the Bridget Shiel murder investigation identifies a compelling new suspect who was recently imprisoned for a double homicide - Christopher Spencer. Lowe investigates Spencer's background, criminal history and cell phone records in the wake of Bridget's murder, sending him to Arkansas to speak with Spencer's family, and ultimately to the prison where Spencer is held to interview him face-to-face. Meanwhile, Benton investigates the death of a young man, shot and killed while selling water on a hot summer day.