Two couples meet in a bar and one of the couples is murdered. When a second couple is murdered in a similar fashion the team suspects a pair of serial killers are on the loose. The case is complicated by leaks to the press and a judge reluctant to issue a warrant. Catherine gets some troubling news about her father's murder trial.

When the lead suspects in Grissom's serial killer case are murdered, Grissom suspects an inside job. Grissom and Brass are at odds when Grissom suggests it was a cop. Catherine and Sara investigate what happened to a college football fan when his bloated body is found in a bathtub.

Grissom and Warrick get the case of an old woman found mummified in her closet. Sarah and Nick arrive to investigate a breaking and entering to find a raped teen. These cases are not as disparate as they first seem. Catherine looks into a gun found by a boy. The gun is connected to a week old murder across town that Warrick caught.

During Vegas's latest Heat wave of triple digit temperatures, Gil and Catherine investigate a baby locked in a car. Warrick investigates a man dead of an apparent heat stroke in his house. Nick and Sarah investigate a woman's body found floating in the lake with a blow to the head.

The team is introduced to the ""Furry"" side of Vegas when a man is found dead on the side of the road, dressed in a racoon suit. Elsewhere in Vegas, a gunshot victim is found in a deep-freezer, frozen solid.

A severed head is shipped to Dr. Robbins from Jackpot, Nevada. Grissom goes to Jackpot to find the rest of the body and gets very little cooperation from the locals. Catherine gets an unexpected gift from her father.

Warrick's appearance at the preliminary hearing on a rape and murder case goes terribly wrong when the only piece of evidence is thrown out on a technicality. Grissom and the team have 24 hours to make the case with new evidence or the killer will go free.

A suspect's infatuation with Catherine results in her taking over a high profile case. The case is a missing woman who aspired to be a showgirl. Sara and Nick are angered since it takes the career making case away from them.

The sheriff is under political pressure to find who killed an air marshall with a car bomb that the sheriff witnessed. Grissom, Catherine and Nick are pressured to produce results. Warrick and Sarah try to find the murderer of the wife of a singer who headlines on the strip.

A teenager is found murdered on a construction site. Grissom, Sarah, and Warrick follow the lead of blood on a hammer. Nick, with an assist from Catherine, tries to find how a woman was killed by a gunshot on her lawn when no one nearby had a gun.

The lone holdout on a jury is found dead in the jury room. The eleven jurors who were voting guilty and who hated the dead juror are the natural suspects. Nick reopens a four year old case when the sister of the victim comes forward with new evidence.

A woman found murdered in her home. Her resemblance to Sara causes Grissom to take a personal interest in the case and forces him to examine the decisions he has made in his life.

Three little CSIs (Grissom, Sara, and Nick)respond to an electrocution at a casino. The casino is hosting Japanese antiquities. The electroctution is just a ruse to steal the central piece of the exhibit. Catherine and Warrick deal with a vampire murder.

A robbery at a grocery store results in a shootout leaving five dead. The police officer at the scene believes Grissom has a grudge against him. The entire team has to process the enormous amount of evidence at the scene.

CSI etterforsker drapet på et ektepar som blir funnet skutt i oppkjørselen foran huset sitt. Det hele minner Grissom om en henrettelse, og han skjønner at det er en rutinert drapsmann han har med å gjøre.

CSI møter nye sider av Las Vegas når de etterforsker et mord i transvestittmiljøet i byen. I området, bedre kjent som Tranny Town, finner politiet liket av en klovn. Mannen hører ikke hjemme i denne delen av byen, men morderen er tydeligvis ikke enig.

En buss som skulle transportere fanger fra ett fengsel til et annet, er involvert i en ulykke. Da CSI kommer til åstedet, finner de en kvinnelig fange bundet fast til understellet av bussen. Dette er ikke et rømningsforsøk – men et drap!

Grissom blir overfalt under avhør av en mistenkt i en brutal drapssak. Brass og flere konstabler kommer ham til unnsetning, men basketaket som følger resulterer i at den mistenkte dør. Til tross for at politiet blir klarert i saken, sitter Grissom igjen med flere spørsmål enn svar rundt mannens uforklarlige fortid.

CSI-teamet gransker åstedet til en husbrann. De har mistanke om at en pyroman herjer i nabolaget. Men da de finner liket av en ung jente inne i huset, avanserer etterforskningen fra ildspåsettelse til mordbrann.

Grissom, Catherine og Nick undersøker dødsfallet til en løper som døde under en konkurranse. Samtidig etterforsker Sara og Warrick en sak der et par ble funnet døde på hotellrommet.

Seks mennesker dør i en berg-og-dal-bane-ulykke i Las Vegas. Ved nærmere etterforskning viser det seg at en av de omkomne allerede var død idet vognen traff bakken.

To collegegutter blir funnet drept etter et forsøk på å svindle et av de store casinoene i Las Vegas. Catherine blir øyeblikkelig tatt av saken da Grissom oppdager at Sam Braun, Catherines far, eier casinoet.

En casinoansatt blir overfalt og voldtatt på vei hjem fra jobb. Hun overlever og identifiserer sin overfallsmann. Men da DNA-prøvene viser at mannen er uskyldig, må Grissom for første gang innse muligheten for at bevisene kan lyve.