With four cases to solve, it will be a long day for every one of our CSIs. Greg has finally found a replacement and is out on his first official case with Grissom as they investigate a shooting at a night club. In order to become a field officer, Greg must pass this last test. Catherine investigates the death of a stripper in a hotel room with multiple blood sprays on its wall. Warrick solves the truth behind the death of a man electrocuted in his own bathtub. Sara and Nick have the strangest of cases as an 'alien' is found half-buried in Area 51.
The team is called in to investigate a dead body found in the drain. The cause of death is quickly concluded as an accident. However, Catherine and Warrick discover pieces of badly deteriorated pieces of human bones in the sewer. The skeleton is that of a teenage boy. The only lead the CSIs have is a house, near the body dump, is full of explosives.
An Amber Alert is sent out when a young girl, Alycia, is kidnapped. She later turns up, wrapped in a blanket stained with her blood, even though she has no injuries. Investigations reveal that she has been giving her elder brother bone marrow transplant and was going to donate one of her kidneys to him. Meanwhile, Catherine has to deal with Lyndsey who was caught hitchhiking.
The death of two women, both obsessed with being young, leads Nick and Catherine to a 'spa' belonging to a doctor. There, Catherine is more self-conscious than ever about her aging. Another death happened in a house recently fumigated to kill insects.
The team investigates two cases. The first, conducted by Grissom, Sara, and Greg, involves a dead woman found in a fountain. Although she drowned, the water found in her lungs does not match that of the fountain. The investigation leads the CSIs to a group of swingers who partied with the victim prior to her death. The second case, investigated by Warrick and Nick, involves the death of a landlord in a gaming arcade. The heavy stench in the room leads to the discovery of another body hidden in a gaming booth.
Starting in 1987, three murders were committed on the Western Las Vegas University campus, one of which provided Catherine Willows to investigate a suspect - John Mathers, security guard of the university. Mathers was arrested and convicted. Two years ago he was executed. But the night of his execution another murder with the same M.O. was committed. Eventually, Mathers turned out to be a copycat, responsible only for one murder, and the serial killer got away. And today, the evidence found by Greg Sanders at a fresh crime scene leads Catherine to the conclusion that ...
Grissom and Catherine are at the Robert Cavallo's retirement dinner. When the sheriff is about to appoint Conrad Ecklie the new Assistant Director for the Crime Lab, Grissom is called away to investigate the death of a young girl at a private party in the Olympia casino/hotel's penthouse. At the crime scene he meets Sofia Curtis from the day shift who works for Ecklie...
A body of a woman, her throat slit, is found in her car next to the highway. Autopsy reveals that Wendy was once a man who underwent a sex change operation. To solve this case, Grissom and his team ventures into the world of transsexual people where no one is as they seem. Their investigation leads them to a therapist with a hidden past.
During a retrial, a fingerprint appears on a matchbook which was formerly not visible to Grissom and his team. This makes Grissom reopen the case. His decision leaves him an easy target for Ecklie who immediately investigates his past handling of cases. Ecklie's agenda is clear. He is out to destroy and discredit Grissom.
An inmate is brain dead at a hospital from a small riot inside a very crowded holding cell. Catherine leads a team to investigate at the police station. The other case involves the body of a young boy found in a trash can. Autopsy reveals that he died from starvation.
Greg is doing his final proficiency test and he has a case to solve. Ironically, he investigates the death of a Sherlock Holmes- wannabe, obsessive to the point of recreating the great detective's living room in his home. He died from a close-range gunshot wound. The murder weapon is not found in the scene although everything other pieces of evidence suggest that it was a suicide. Working under Catherine, Nick and Warrick works on a case of a dead guy found in his car which veered off the highway. Dr. Robbins cannot find the cause of death and it is left to the two ...
A severed head of a woman, her hair brutally ripped off, is left in a newspaper vending machine. Found inside her mouth is a snake from Mexico. The murder fits the lyric of a Mexican song. The second case involves a dead salesman found inside a van with a wheelchair left behind in the back. The wheelchair belongs to a dead woman.
The bodies of two women are found covered in tar in a pit. The body in the bottom part of pit cannot be identified. The one on top was a mail-ordered-bride who died approximately 2 years ago. The prime suspect is her husband who claims that she disappeared and has already 'purchased' a new Asian wife.
A Lexus belonging to a young mother is found with a flat tire on the highway. The body is later found. Another case involves the death of a hunter from a bear. The bear, after attacking the man, also died. Investigations reveal that the bear, Tippy, was purchased by a broker claiming to be representing a zoo.
Bruce Eiger, a powerful Las Vegas casino mogul, is found dead on his front steps. The media is all over the case. Ecklie assigns Grissom to the case despite it being official Catherine's. Eiger had a dark secret. He liked being treated like a big baby.
Catherine, Warrick and Nick investigate a shotgun killing in the desert. What they come across however is a beaver dam full of money. When they subsequently learn that the victim worked at setting the spread for sports betting, they think he may have a betting scam of some sort. Grissom, Sara and Greg investigate a death in a hotel where someone is found suffocated in his bed. He was staying in a hotel hosting a convention for overweight people and was quite popular with the ladies.
A female flight attendant is brutally raped and killed in her hotel room. Ecklie brings a five-year-old cold case to Grissom and his team which bears a striking resemblance to the new case. Catherine's team investigate the death of a young boy in his own bed. He was beaten to death while his parents and older brother were in the house.
Greg, Sara, and Gil Grissom investigate a scene of bush fire which led to the death of man and the 3rd degree burn of another woman. Catherine, Nick and Warrick solve a case involving the death of an entire family. The father is found dead, apparently from a suicide, on his bed. The mother was shot while running downstairs. Their little daughter drowned to death in the pool.
This episode chronicles four crimes which are in themselves interconnected. One involves a stolen Hummer truck which was recently won by a couple from a convention where a dead woman was found. Prior to this, one of the convention's employee walked in on her dead trainer inside his very secured house. Lastly, the body of a twelve-year-old boy was left on a street bench.
Captain Jim Brass journeys to LA after Ellie asks for a favor in investigating her friend's disappearance. There, with the help of Warrick who is in LA for a conference and a friend in LAPD, Brass finds his investigation interrupted by higher powers. While he and Warrick ultimately are able to find Ellie's friend's murderer, he is unable to bring the perpetrator to trial. Disappointed, he leaves LA and return to Las Vegas.
Sara accompanies Grissom to a mental hospital where one of its inmates has been murdered inside his room. Interviewing patients prove to be harder than usual as most of them are mentally unstable. While the two CSIs are there, they uncover more than just the crime. One of the most shocking discoveries involve a patient with a dark childhood, which is still haunting him, and a nurse with a secret.
After an exhaustive day, Catherine stops by a bar where she has a fling with another customer. As she is leaving, he gives her his number on the bar's match box. Later on that night, Grissom calls in for a favor as he is short on staff. A woman was murdered. Prior to her death, she was seen with the same man who was hitting on Catherine in the same bar. A similar match box with a phone number inside, found on the victim, further points to this man as the main suspect.
Greg and Sara work on a case of two university students who mysteriously end up dead in a dorm room. Catherine, Warrick, and Nick investigate the death of a man found in what looks like a crop circle. With everyone busy on cases, Ecklie must work on a case himself. Unfortunately, the body disappears from the morgue.
With its desperate attempt to ransom Nick's release failed by their enemy's fanatical revenge, the CSI team must use all their investigative talents to find Nick, whose perilous situation is becoming all the more horrific by the minute.