The killing of a prominent casino owner's wife attracts the attention of a dynamic special agent from the FBI's cyber crime division in Washington.
Grissom and Catherine probe a bizarre case in which a man dressed in a full-body raccoon suit is shot and then hit by a car on a dark stretch of highway.
The team investigates an assault on a casino employee and the CSIs soon realise they are after a serial rapist. Meanwhile, Sara is arrested for drink-driving.
Grissom visits a small town to investigate the death of a man whose severed head was found by a dog. Elsewhere, Catherine receives an unexpected gift from her father.
Grissom and Catherine discover a dead colleague during a desert race for cops. Their investigation soon turns up two more bodies and they suspect foul play.
Catherine and Warrick suspect a serial arsonist is at large after a house fire kills a girl in a neighbourhood where a blaze broke out just a few days before.
Catherine leads the investigation when a mutilated female body is discovered tied to the undercarriage of a bus carrying prisoners from a women's jail.
The team believe they are dealing with the death of a transvestite but, during the autopsy, they find his make-up is face paint and he is actually a clown.
Grissom, Sara and Nick probe an electrocution at a Vegas casino, while Catherine and Warrick investigate a murder with vampiric overtones.
A woman is found murdered in her home, but her uncanny resemblance to Sara causes Grissom to take a personal interest in the case.
Catherine takes over the high-profile case of a missing model when the prime suspect, a photographer, insists on speaking only to her.
The team investigates when a man and his porn star wife are murdered, while things get personal for Catherine when Grissom talks to her about her evaluation.
A robbery at a grocery store ends in a shoot-out that leaves five dead and the police officer at the scene believes that Grissom has a grudge against him.
Sheriff Atwater suspects terrorists are responsible for a car bombing that killed three people outside a casino, but Grissom isn't so sure.
The temperature moves into three figures during Vegas's latest heat wave, with Grissom and Catherine taking on the case of a baby locked in car.
The only piece of evidence in a rape and murder case is ruled inadmissible, leaving the team 24 hours to find new evidence before the accused killer is freed.
The mummified remains of an elderly woman are found in a closet, while Sara and Nick make a shocking discovery when they probe a case of breaking and entering.
In the concluding part, the investigation into the double homicide uncovers two more murders, with Grissom believing that a police officer may be involved.
Part one of a two-part story. When two couples are murdered in similar circumstances, Grissom and the CSI team suspect that a pair of serial killers are at large.
Grissom, Sara and Nick investigate a horrible accident on a roller coaster while Catherine and Warrick look into the murder of a 13-year-old girl.
A murder in a parking garage is followed by an incident in an interview room, leading the CSI team on an investigation that contains shocking discoveries.
When the lone dissenting voice on a jury is found dead in the jury room, the other eleven jurors, who were all voting guilty, are the natural suspects.
Grissom pulls Catherine off a case when it turns out that her father is the chief suspect. Elsewhere, Nick beats Sara to a promotion and tempers start rising.
Grissom, Sara and Warrick investigate the murder of a teen found beaten to death on a construction site, with the murder weapon seemingly being a hammer.