A woman called Laura Garas is buried alive, screaming for help. A recorded message instructs, "Bring two million in hundreds to Charleston & Third in three hours or your wife dies. Stop me from taking the money she still dies." At the Garas home, Brass attempts to dissuade Laura's husband, Jack, from paying the ransom, while Grissom & Nick scrutinize the message for clues. Observing a gap of silence and a low-frequency buzzing sound, they speculate that Laura's buried in the desert near power lines. Sara does a walk-through at the site of the apparent abduction. There are "points of disturbance" everywhere - all of which point to a struggle. When Grissom joins her, he notices dirt on the bedroom carpet. Checking outside, a sweet scent draws them to a handkerchief lying on the ground, seemingly doused in Halothane - a liquid anesthetic.
Catherine & Warrick are assigned a disturbing hit-&-run of a young girl, Renda Harris. Finding only a common car-paint scrape on the girl's scooter, they return to the lab, where Doctor Williams shows them a partial license plate number visible on the girl's body in a bruise.
An analysis of the dirt from the Garas home reveals traces of gold and cyanide. Grissom explains that miners use cyanide powder to draw gold to the surface. He & Sara take off in a helicopter for the three nearest nearest sites that fit the bill. Unable to dissuade Jack Garas from paying the ransom, Brass trails him to the drop site, where Garas heaves a gym bag into a trash can. When a young man in a baseball cap eventually retrieves it, the police converge.
Simultaneously, Grissom & Sara scour the desert with a forward-looking-infrared camera. They spot the glowing image of a writhing body underground. Frantically, they dig until Laura is unearthed.
A hit on the partial license plate number brings Catherine & Warrick to the home of Charles Moore, a gentlemanly seventy-three-year-old. Although he claims his car was stolen, a search reveals it's in the garage. Moore confesses that he was behind the wheel. He spotted Renda in the middle of the road, went to brake, & instead stepped on the accelerator.
When Grissom interviews Laura Garas at the hospital, she only recalls being grabbed from behind in the hallway of her home. The last thing she remembered was something being clamped over her mouth. Laura can't remember anything about her assailant. Grissom asks for a DNA sample to check the duct tape that was used to muzzle her and to use while examining the truck belonging to the man caught at the ransom drop-off site, Chip Rundle, Jack Gara's personal trainer. Brass informs Rundle that his prints have been found on Laura Gara's makeshift coffin. Rundle explains that he helped Jack move crates. Rundle is released, but Brass has recorded the interrogation for comparison with the ransom message.
Warrick & Catherine examine Moore's car. They notice that the driver's seat is pushed too close for his height & the car radio is set to blast a hip-hop station. They ask Moore if anyone else drives his car, just as his grandson, James, enters. Mr. Moore admits that after hitting Renda, he'd banged his head. James drove him home. Neither of the CSIs believe his story.
The AV lab has just matched Rundle's voice with that on the ransom message. Sara asks Grissom to help her reconstruct Laura's abduction after finding hair strands in the front passenger seat of Rundle's truck. She notes that fibers from the seat's sheepskin cover were found on the back of Laura's sleeves, which could only have happened if she was sitting normally. A blood test confirms that Laura never ingested the halothane. Brass enters, saying Rundle now wants to make a deal, but Grissom stops that idea in its tracks as he knows what Rundle has to offer ... Laura Garas, his accomplice.
Taking a closer look at Charles Moore's car, Catherine retrieves a small piece of tooth embedded in the steering wheel. When they ask to see his teeth he plucks out an entire set of dentures. James is arrested & Charles is released. A sympathetic Warrick accompanies James & offers advice before he's taken into custody. Warrick also writes his cell number on James's hand, just in case James needs to contact him if trouble arises.
Laura strenuously denies any relationship with Rundle. Sara claims they staged the abduction as part of a plan to run away together with a chunk of Jack's fortune. To drive the case home, Nick plays three versions of the ransom recording. The final recording and the most damning recording isolates the previously inaudible sound of Laura saying, "Hurry up, Chip!" As Laura is taken away, an angry Jack Garas asks Grissom why she didn't just give Rundle up. "Self Preservation," Grissom explains. "If she rats on him, she rats on herself."