Two couples meet at a bar, but only one couple will leave alive. However, after the second couple turn up dead, murdered in a similar fashion, the CSIs begin to suspect that two serial killers are on the loose. But when information about the case is leaked to the press, and when the team has a hard time obtaining a search warrant from a judge, the case becomes increasingly complicated. Meanwhile, Catherine learns some disturbing information about her father, 's murder trial.

The team is able to come up with some lead suspects in the serial murderer cases, but when their suspects are murdered, Grissom begins to suspect an inside job , and suggests that a cop might be the leak, upsetting Det. Brass. Meanwhile, Catherine and Sara are sent to investigate when a football fan, 's bloated body is found in his bathtub.

When an old woman is found mummified in her closet, Grissom and Warrick are dispatched to investigate the scene. Elsewhere, Sarah and Nick investigate a breaking and entering scene and find a raped teen at the site. Soon Sarah and Nick realize that their case and Grissom, 's case are not as unrelated as they seem. Meanwhile, Catherine examines a gun found by a young boy and is able to connect the gun to a murder case from across town.

Las Vegas is hit with record breaking, triple-digit heat and heat related deaths begin to pop up around town. Grissom and Catherine investigate when a baby is found locked in a sweltering car. Meanwhile, Warrick looks into an apparent heat stroke death while Nick and Sara investigate when a woman, 's body is found floating in a lake with a serious head wound.

The CSIs are emerged into the little known , furry, side of Las Vegas after a man is found dead dressed in a raccoon suit. Meanwhile, the team looks into a gunshot victim whose body is found deep-frozen in a deep-freezer.

Dr. Robbins receives a severed head from Jackpot, Nevada, sending Grissom to the town in order to find the rest of the body. While in Jackpot, Grissom finds it hard to solve the case when the local police department and residents show very little cooperation. Meanwhile, Catherine is surprised when her father presents her with an unexpected gift.

Warrick, 's appearance at a preliminary hearing for a rape and murder case takes an unexpected turn when the key piece of evidence is thrown out of court. Now Grissom and his team have 24 hours to come up with more evidence or the murderer will be set free.

When a suspect develops a strange infatuation with Catherine, she ends up taking over a high-profile case about a missing woman who wanted to be a showgirl. Meanwhile, Sara and Nick are furious at Catherine for taking over the case that they thought would help make their career and possibly earn them a promotion.

After the sheriff is pressured to find the killer who murdered an air marshal by means of a car bomb, he, in turn, pressures Grissom, Catherine, and Nick for results. Meanwhile, Warrick and Sara work to find out who murdered the wife of a high-profile Las Vegas performer.

When a teenager is found murdered at a construction site, Grissom, Sara, and Warrick work to track down the killer by using a bloody hammer. Meanwhile, Nick and Catherine try to figure out how a woman was shot and killed in her lawn when no one nearby the scene of the crime was near a gun.

During a high-profile murder trial, the single holdout on the jury is found dead in the jury deliberation room. With the other eleven jurors, who all voted guilty, showing obvious dislike for the dead juror, they immediately become the main suspects. Meanwhile, Nick reopens a case after the sister of the victim approaches the department with new, ground-breaking evidence.

A woman is found murdered in her home, and her uncanny resemblance to Sara causes Grissom to take a personal interest in the murder investigation. As he probes deeper and deeper into the case, Grissom begins to reexamine his life and the decisions that he has made up until now.

Grissom, Sara and Nick are sent to investigate when a man is electrocuted at a casino that, 's hosting Japanese antiquities. The three CSIs discover that the electrocution was a distraction used to steal the main item at the exhibit: an antique samurai sword. Meanwhile, Catherine and Warrick look into a , vampire murder, .

After a grocery store robbery goes wrong, a shootout results that leaves five individuals dead. With the large crime scene and enormous amount of evidence to collect, each of the CSIs are called to investigate the scene. Meanwhile, the police officer at the crime scene thinks that Grissom has a grudge against him.

The CSIs investigate the scene of a crime where a man and his porn star wife were killed execution style. Things begin to become personal for Catherine when Grissom calls her in to talk about her evaluation. Meanwhile, Brass is lead to believe that Sara might have a personal problem.

Catherine and Sara investigate the death of what they first assume to be a transvestite. However, at the autopsy they learn that what they thought was make-up is actually face-paint leading them to one conclusion , he was a clown. Meanwhile, Grissom, Nick, and Warrick look into the death of a man, who worked in a drug recovery center, in the homeless part of town.

An arm falls out from underneath of a bus and after an investigation of the bus, the CSIs find the remains of the body stuck beneath the bus. The bus in question was carrying inmates from a women, 's correctional facility, leading the CSIs to believe that an inmate tried to escape during transport. But when tests reveal that the victim was dead before the transport began, the case becomes more complex. Meanwhile, Grissom looks into a case involving a man stabbed once in his chest and four times in the back , all wounds being exactly the same height.

A violent murder occurs in a casino parking garage and surprising events in the interrogation room leads the team to several shocking discoveries about the murder. The case revolves around three interconnected incidents including a missing child, a missing woman, and a body that has been dead for a while.

Warrick, Catherine, and Nick are assigned to find the cause of a house fire that resulted in the death of a teenaged girl. The trio assumes arson since the fire was in the same neighborhood as a previous arson fire. Meanwhile, Grissom and Sara team up to investigate when a man, who was competing in a word game tournament, is found dead with letter tiles in his stomach.

Grissom, Catherine and Nick look into the death of a runner who died during a competition. Meanwhile, Sara and Warrick investigate when a couple is found dead in their hotel room in an apparent murder-suicide. With a , cop, ' competition in town with 20,000 police attending, the investigations become very interesting being that all of the suspects and victims are police officers.

At an amusement park a roller coaster runs off of the track, resulting in six deaths. The CSIs are sent to decide if the incident was an accident or the result of foul play. Meanwhile, Warrick and Catherine work to find the killer of a thirteen year-old girl.

Two men are murdered after they are found cheating in one of Sam Braun, 's casinos. Grissom and Warrick take over for Catherine after her personal ties to the case get her thrown off. Meanwhile, Sara is devastated when Nick gets the promotion that she wanted.

A casino employee is brutally beaten and raped on her way home from work, and survives the attack. Though she is able to identify her attacker, a DNA test sets the suspect free. Upon hearing this, Grissom must decide whether or not the evidence can be wrong. Meanwhile, Grissom rescues one of his co-workers that happens to find themselves on the other side of the law.