Grissom and Catherine investigate when a leg is found severed from a body in a lake. They suspect the husband and boyfriend. Meanwhile Sara and Nick investigate a fraternity pledging gone terribly wrong.

A woman is abducted from a mall parking garage. She's raped, beaten, shot and left for dead. Sara collects evidence from her and grows attached to her. Nick and Grissom analyze the crime scene. Catherine and Warrick are given boxes of evidence from a shooting that goes to trial in four days. The CSI who had the case has quit and they have to prove what happened. To make Catherine's life more complicated, Eddie has taken out a second mortgage without her knowledge.

Grissom investigates a possible suicide at a high-profile construction site. Catherine takes on a case with a teenage boy who dies while in session with his female psychologist,

Grissom and Nick investigate the death of a book restorer while Catherine and Sara are called to the scene of a fatal train crash.

Catherine is ordered by a kidnapper to accompany a man who is to deliver $1 million in ransom to him or else he will kill the man's mistress.

A bus carrying 23 passengers from Los Angeles to Las Vegas crashes less than 40 miles from its destination, killing nine people. Tthe CSIs soon discover that a recent parolee was on the bus, but is now unaccounted for.

Grissom and Catherine investigate the stabbing death of an 80-year-old woman who lived in a run-down house full of cats; Nick and Sara comb through the remains of a car bombing that was, apparently, a murder plot gone awry.

Season Finale. The CSIs investigate when the body of an unidentified young woman is discovered stuffed in an overturned shopping cart near a freeway underpass. Her horribly disfigured and partially decomposed face is a nightmare of blood, scabs and scars, as if she'd been shoved into a fan. A huge circular hole dominates her left cheek. Someone not only wanted her dead, Grissom reasons, but ""they wanted her ugly."" Adding to the mystery are the cart's other contents: an expensive handbag, fashion magazines and a leather day planner with notes written in code.

Grissom and Catherine investigate the murder of a wealthy couple who are discovered just outside of their glamorous Las Vegas house, which was up for sale. Meanwhile, Sara probes the death of a cheerleader who is found eviscerated on a soccer field, her organs having been ingested by her killer.

A middleweight boxing champ dies in the ring after taking a brutal beating from his nemesis, but Grissom finds evidence that points to murder. Outside, in a nearby parking lot, Catherine works a crime scene where a Los Angeles gang member was gunned down, apparently by a rival gang. Also, Nick investigates a jewelry-store robbery.

Grissom, Warrick, and Nick investigate the case of man who apparently was murdered and pushed off a six story building. Grissom's involvement is cut short by renewed hearing problems. Catherine looks into the murder of man outside of his regular bar.

Grissom and Catherine investigate the grisly meat grinder murder at a slaughterhouse. Warrick and Sara look into the apparent suicide of a troubled young woman.

Grissom investigates the murder of two men that leads him to a new encounter with Lady Heather. Catherine is desperate to find out what lead to the near death of her daughter and why her ex, Eddie, disappeared.

An elderly woman crashes her car into a crowded restaurant. One of the patrons is Sara's paramedic boyfriend. Grissom and Nick investigate the possible carbon monoxide murder of a woman in her home.

Grissom and Catherine investigate the murder of a despised comic who died onstage, apparently after drinking from a tainted bottle of water. The case grows more puzzling when a 15-year-old boy dies in a convenience store after drinking the same brand of water. Brass reopens a woman's accidental-death case after spotting the deceased's husband in a flashy new car with a trophy date on his arm.

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.

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.

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 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.

Two men are found murdered after scamming Sam Braun's casinos. Grissom and Warrick investigate after Catherine is thrown off the case. One of the suspects is the son of a man Braun caught cheating. Nick gets the promotion that Sara coveted.

A woman is found dead in a hotel suite with symptoms of the ebola virus. Another woman is found dead with similar symptoms. Catherine and Nick investigate. Sara and Greg with help from Grissom try to determine how a the owner of a home was killed. His home was tented for infestation.

A woman who was pulled over by police is found murdered two miles up the road from the stop. It's not long before Robbins determines that the woman is, genetically speaking, not a woman.

The swing shift has a busy time. Warrick looks into the murder of man by someone who apparently needs a wheelchair. Nick looks into the murder of woman in the subculture of the narcocorrido, songs about drug murders. The night shift is slow and lends help to Catherine's team.

When a major Las Vegas player is found dead, Ecklie orders both teams to investigate the case. The man who had secrets on everyone in Vegas had a very big one of his own.

Grissom and Sara investigate the murder of a mental-hospital patient and quickly narrow down the suspects to a handful of other patients and staff members.

Two amorous freshmen are found dead on a sleeping bag in a dorm room, and Sara and Greg run into one dead end after another as they try to determine why the students were killed. Warrick, Nick and Catherine figure out how a man is found dead in the center of a crop circle. Ecklie is called into duty for a man found dead in his car and his body later goes missing.

The two forensic teams come back together under the leadership of Grissom and Catherine just in time to tackle three separate investigations: a murdered couple found in bed in a suspicious trailer explosion; a beautiful stripper discovered dead and dumped in the worst part of town; and two bodies found baked and decomposed after spending five days in the trunk of a car exposed to the hot Vegas sun, forcing the CSIs to ""wrap"" up the evidence and bring it back to the lab for further analysis.

Nick takes the lead on a case where in the house a family of four, three pools of blood are found. Nick thinks that the little girl may still be alive, but Sara is doubtful, thinking that Nick's recent near-death experience is affecting his judgement.

The CSI's are called out to investigate the disappearance of a boy whose father died four years ago. Soon a couple is arrested at a convenience store with a boy matching the description of the missing kid. The only problem is they both claim it is their son. Both parents have exactly the same picture of the boy, with a scar on exactly the same place on his face. They hope a DNA-test could confirm who the real parents are, but when this information comes to light, it lead to another bizarre twist, possibly murder.

The CSIs investigate the gruesome murder of Lady Heather's estranged daughter, Zoe, who was found in the middle of the Vegas desert.

Three tourists are beat up, badly. One is dead, Alfonzo. Jessica is badly beaten but is still alive. Stanley, the last tourist is saved by Greg who ends up severely hurt in turn and ends up hospitalized after having to make a life altering decision.

While investigating an elderly woman's murder, Grissom receives a miniature crime scene replica; Greg attends a hearing to ascertain his culpability in a teenager's accidental death.

Catherine testifies in a murder trial in which a man is accused of murdering his own mother three years ago, but the suspect is found not guilty. Catherine, however, believes he did commit the crime and that he may also have killed two other people, so she sets out to find the other victims. Grissom prepares to leave on a four-week sabbatical.

Grissom returns from his sabbatical; Keppler is put into a compromising position when the bodies of a Trenton police officer and a hooker are found in a hotel room. The man who found them is a retired New Jersey cop and close friend to Keppler, who doesn't reveal their relationship.

Several suspects in a murder case are UFO-club members who believe shape-shifting aliens have been working to conquer the human race for centuries

The CSI team investigates two unusual cases, one involving the suspicious death of a go-cart racer who took his hobby to the highway and paid the price with his life, and a murder at a hip new restaurant where patrons dine in the dark

Grissom and his team investigate when an actress is killed on the set of a horror porn film.

Two murders that happen during Las Vegas' annual bull riding rodeo are investigated by the CSIs, who find that the murders might be connected to illegal bull breeding.

Grissom and his team battle the flu when they are called upon by D.D.A. Klein to investigate the deaths of several key witnesses for a grand jury case against a dangerous Las Vegas gang.

After Warrick is shot in a Las Vegas alley, the CSI team comes together to deal with the aftermath.

The team has a hard time investigating a shooting in Koreatown when none of the witnesses will talk about the crime.

The first day on the job for Dr. Langston turns from bad to worse when a simple burglary case quickly overlaps with a complicated arson and homicide case.

When the CSIs are called to a murder scene at a familiar motel, Nick is thrown for a loop as he pieces together three separate murder investigations that all took place at the same establishment over the course of a year.