After a man is found dead in a "human hamster ball", a clear plastic ball used to roll down hills, the CSIs determine the victim was beaten from an assailant outside of the ball. They track the ball's path back to the victim's residence and identify him as Zack Fisk. While collecting evidence including a statue matching the indentations on the hamster ball, the team learns of Zack's weird sexual fetish, claustrophilia, the love of being in a confined space with limited oxygen. A woman in Zack's video tape engaging in claustrophilia is soon found dead in a box that was sealed and mailed out with Zack's fingerprints on the label. They question her husband, a ranch worker who admits to allowing his wife to participate in acts of claustrophilia with Zack, but the special-blend horse feed found on the statue used as the murder weapon implicates him and he admits to killing Zack.Meanwhile, the team teams up with swing-shift CSI, Dawn, to investigate the case of a serial rapist. Based on the preparedness of his attack on the third victim, Amy, they determine the first two rapes were rehearsals and that Amy was the intended target. During the course of the investigation, Dawn goes missing and it comes to light that she mistakenly believed her teenage son was dead. The same materials found at each of the crime scenes lead the team to a trailer park where they discover DNA linking the father of Amy's ex-boyfriend to the crime. After apprehending him, they find Dawn unconscious from attempted suicide and rush her to the hospital.