A hiker leads intelligence to a young woman being held captive in the woods near Chicago; a former relationship of Halstead's comes back into the picture, much to the surprise of Lindsay.
When a controversial misogynistic comic is accused of rape, Benson is happy to arrest him, but Barba feels the case is weak.
Pete's brother (Kyle Secor) brings their mother (Louise Fletcher) in for a consultation; Violet catches Sheldon asking her archenemy for a date; Cooper treats a young music prodigy who has a brain tumor.
When a student is discovered murdered at Lindsey's school, the investigation takes a sharp turn when the CSIs uncover an unlikely connection between the boy's death and atrocities of the past.
The CSI team investigates the bizarre death of a man who was killed not once, but twice. Sharon Osbourne guest stars as Elise Massey, the manager of a billiards championship.