Sheriff Rory Atwater is leaving the Orpheus hotel and witness a car bombing, where the driver, the valet and the bellhop die. Grissom and Catherine arrive to investigate the crime scene and gunshots start. Grissom finds that the bullets are in the trunk in bag. Nick and Capt. Brass help the investigation. Soon they learn that the driver is Air Marshall Adam Watson, and the car was rented in an agency. Nick puts together the pieces of the bomb, which was a pipe bomb connected to the car clock. Soon they conclude that the victim might have been the previous user of the rented car since the timer was not accurate. Meanwhile, Sara, Warrick and Det. Louis Vartann investigate the death of Amelia Reuben, who is the wife of the successful singer Myles Reuben. They conclude that Myles, his manager Sam Hopkins and a hotel waiter were the last persons to see Amelia alive, and the autopsy and Greg's investigation concluded that she was poisoned.

A juror dies during a trial in a heavily guarded safe house. A four-year-old case of a missing woman is reopened when the woman's sister gives the CSIs new evidence she withheld during the original investigation.

While trying to pass a bus on the highway, an arm strikes the windshield of the car of a couple. Catherine, Nick, Sara and Capt. Brass investigate the crime scene and find pieces of a woman secured by white strips of clothes on the bottom of the bus that was carrying inmates from a prison to a church. They believe the woman was trying to flee from the correctional facility. Soon they learn that the victim is Antoinette "Baby Girl" Stella that would be released on the next month. Sara and Nick go to the prison to try to understand why Baby Girl decided to escape. Meanwhile, Grissom and Warrick investigate the murder of Adanto Adams who was stabbed to death at the home of his intellectually disabled brother Zero. Soon they meet Zero and his guardian Frank Samuels and they learn that Adanto has promised to his beloved brother Zero that they would be rich. Warrick gets the videotape of the casino where Adanto went to play blackjack and lost a fortune.

During the police marathon in Las Vegas, Grissom sees a runner outside the road and drives his car to the place, leaving Catherine alone. He finds a police officer dead. Dr. Robbins find that the victim was in excellent shape, but he had ingested two substances that combined killed him. Meanwhile, Sara, Warrick and Det. Louis Vartann investigate the murder of officers Manny Senteno and Patricia Fielding in a hotel room. Warrick's first impression is that might be a murder-suicide case. Soon they find fingerprints of the police officer Lydia Lopez and learn that she was lodged in the next-door room. When they look inside the room, it is completely trashed. Lydia says that she had sex with a Manny once a year during the marathon and she believes that her husband Archie Lopez might have followed her and trashed her room, but would never kill Manny and Patricia.

When Linley Parker survives a rape attack, the CSI team investigates the case. Linley identify her aggressor Dr. Todd Coombs, but their DNA do not match and Todd is released despite the identification. His brothers become the suspects based on the DNA results, but they do not find the guilty. When Linley is murdered, the CSI team discovers new genetic condition in the case.

Greg has found a replacement in the DNA lab, Chandra Moore, and introduces her to the co-workers. Capt. Brass, Grissom and Greg, in his first case, investigate the death of an unidentified victim with a shot in the forehead in a shooting in the nightclub owned by Manny Brazil. He says that he does not know how the gun has passed through the metal detector. Catherine and Det. Louis Vartann investigate the murder of a woman covered in blood in a hotel room. The man, Carl Johnson, also covered in blood, tells to the detectives that he has never seen that woman before. Soon they learn that the victim is the stripper Nicole "Raven" Richards that drugged Carl to rob him. Warrick and Det. Chris Cavaliere investigate the death of Lance Frazer, a loser that died in the bathtub electrified by heat exchanger causing a short circuit in the motel. Soon Warrick learns that Lance hit a fifty-thousand-dollar jackpot on the previous night. Nick, Sara and Det. Travis investigate an "alien" buried in a shallow grave near the Area 51.

Dr. Robbins concludes that a woman covered with red blotches has not died of Ebola. In the autopsy, he learns that the woman is Julie Stern, who was recovering in the hotel from a cosmetic procedure. He also tells to Catherine that she had urine in her stomach and signs of heavy metal poisoning. Catherine and Nick interview her doctor, Tony Malaga, who owns an expensive clinic. When Dr. Robbins finds the same symptoms in the autopsy of Renita Loakes, they return to the clinic with a warrant to get their medical information. Meanwhile, Grissom, Sara, Greg and Capt. Brass investigate the death of Elliot Beckman, whose house was fumigated and his body was found inside. The exterminators tell them that the house was supposed to be empty when they released the gas.

While giving his testimony in a retrial, Grissom sees fingerprints on a matchbox that he does not recall. The victim Max Larson was found dead I his hardware store hit by a wrench. He requests a recess to the DA and reopens the investigation of the case. He follows the protocol and assigns Catherine, Warrick and Nick to investigate the case again and why they have missed the fingerprint in their investigation. Ecklie asks Sofia to investigate Grissom's cases and begins a witch hunt in the laboratory. Meanwhile, Sara, Greg and Det. Louis Vartann investigate the case of a John Doe, who died after shooting his own leg. When they succeed to find the register of the gun, they find clue of another case.

Grissom, Sofia and Greg investigate a gang shooting with two victims. Out of the blue, Greg finds the body of a young boy dumped in a trash bin. Sara and David Phillips join the investigation. Dr. Robbins notes in the autopsy that the boy was around five years old, was abused with several recent fractures and died of starvation. A further investigation identifies the boy as Devon Malton and Sara and Capt. Brass visit the foster home where he lived with Lorna Tenney. Meanwhile, Catherine, Nick, Warrick and Det. Louis Vartann investigate the case of the prisoner Samuel Mendez that was beaten up in a riot in a cell and now is brain dead. Warrick sees a gun in the cell that was under Samuels body. Lt. Arthur Chen that is the responsible for the prisoners has an argument with Warrick when he comments about a sloppy police search and abuse of force. Soon they learn that Samuel Mendez is not the wanted criminal but an innocent namesake.

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 man is observing the sky with a telescope when, out of the blue, he is burned by a blaze. Grissom and Sara arrive to investigate the scene when Grissom finds a woman still live but completely burned. They believe it was arson and Sara uses the fingerprint in a broken bottle of cheap vodka to identify the truck driver Patrick Bromley. Meanwhile, Catherine, Warrick, Nick and Capt. Brass investigate the murder of the Stewart family, where the parents were shot and their five-year-old daughter Dani drowned in the swimming pull. Nick believes in the murder-suicide theory while processing the evidences. When they learn that the DNA in both cases belongs to the burned woman, they realize that the cases are the same.

When a Hummer in the wrong way runs over an old Fiero, Grissom meets Capt. Brass to investigate the scene. He learns that the Hummer's driver has fled and the Fiero's driver is alive in the hospital. At a car convention, when the host Mr. Daluca opens the curtains to show the latest RV model to the audience, there is a dead woman. Warrick and Det. Louis Vartann learn that the victim is the twenty-nine-year-old model Lisa Schumacher. Dr. Robbins tells Catherine that Lisa was asphyxiated and she had sex before her death. Daluca becomes their prime suspect. Meanwhile, the model Gwen that is working at the convention, goes to the house of her personal trainer Paul Charles to workout and sees him dead through the window. Greg and Sara investigate the crime scene while Dr. Robbins carries out the autopsy. When he sees a black substance in his eye, Hazmat takes Sara and Greg to the decontamination shower. When the body of a boy is found on a bus stop bench covered by a blanket in front of a laundromat, Nick investigates the case. Dr. Robbins tells Nick that the cause of death was asphyxia from heat damage. They identify the victim is Chase Ryan and Nick tries to understand what might have happened to the boy.

After a tough day at the work, Catherine invites Warrick and Nick to drink in a bar. She goes alone and meets Adam Novak, a stranger that fives his phone number in a matchbook. He offers to go to her car with her, they kiss each other and Adam turns brutal when she does not want to have sex with him. She hits her head on the door of the car and goes home. While sleeping, Catherine gets a call from Grissom and heads to the crime scene, where Alice Granger is found dead with a shot in her head. When Det. Vartann find her car nearby the bar where Catherine was, she goes with him to investigate. When she finds a matchbook in the belongings of Alice with a phone number, she heads home to find Adam's matchbook, but it has been thrown in the garbage. Their further investigation indicates that her ex-boyfriend, Jeff Simon, might be the killer, but he had a strong alibi. Catherine tries to tell to Grissom about her possible involvement in the case, but he does not give much attention to her. But when a second victim is found with the same M.O., they realize that the killer might be the same.

When the university students Paula Levine and Trip Wilmont are found dead on the floor after having sex in Trip's dormitory room, Grissom, Sara, Greg and Capt. Brass investigate the case. Grissom leaves the case since he has to go to the court and Sara and Greg use the monoxide carbon detector to look for a source, but they do not find any monoxide carbon in the room. Meanwhile, Brass talks to his next-door neighbor Zack Capola, who says that Trip and him were just mates, not friend. Sara and Greg proceed the investigation. Meanwhile, Catherine, Warrick and Nick join to David Phillip in the middle of a crop circle to investigate the death of a man. In the autopsy, they learn that the victim has urinated in his underwear. When the CSI team locates the owner of the helicopter that was in that area, they learn what has happened to Kevin Staniland. Meanwhile, Det. Louis Vartann finds that no investigator is available and Conrad Ecklie is forced to go with him to the Tangiers since there is a dead body needing to be processed. They learn that the victim is James Billmeyer from New Jersey and Ecklie requests the shoes of the woman that found the body since she stepped on the blood. When James' body vanishes from the morgue there is a further investigation.

CSI team goes back to investigate crime scenes as a team, re-united together after the traumatic experience in season five finale. Nick's kidnap case audio tape arrives at the laboratory.

After a massive shootout between the LVPD and a Latin American mob gang, the CSI team have to find and process hundreds of bullets to determine exactly what happened.

The CSIs continue to process the evidence collected from the high-speed chase. They must also find the bullet which killed a police officer to determine who shot him.

Mrs. Cutler is found dead, shot through the mouth, in her own home, which shows no signs of forced entry or disturbances. Her husband, Mr. William Cutler, is missing, only to be found later, alive, at his office where all of his co-workers were shot dead. He left the bloody scene with only a minor injury. All of this quickly becomes a hostage situation when Mr. Cutler, after shooting a security at a casino, holds a woman hostage.

CSI is caught in a race against time to catch a failed artist-turned serial killer who is leaving his victims in unusual poses all over Las Vegas.

CSI discovers two dead bodies in the same dumpster. One committed an armed robbery in a stolen police uniform, and the other is the teenage daughter of a South American drug lord.

When a new murder leads to a connection with an infamous serial killer, Grissom secretly joins the class of well-known criminal pathologist Dr. Raymond Langston to gain access to the killer and get a crack in the case.

The unit takes on cases involving two employees killed after hours in a chicken restaurant, and a struggling mortgage broker's wife who was killed from swallowing a lethal amount of toothpaste

CSI gets three new dead bodies, and all three cases have a connection to the same con artist with multiple identities.

Nick volunteers on his birthday to take a case involving a 16-year-old girl found dead in the parking lot of a seedy hotel, because he got to know the girl while investigating other cases at the hotel over the last year.

Dr. Robbins determines that a number of unsolved deaths are actually from rabies, and that they are connected to a tattoo parlor and a former medical examiner from Reno who runs it.

CSI tackles a case involving a young man who was brutally raped and beaten, and a case involving the shooting death of an electronics store owner. But they soon discover that the two cases are directly related.

The CSIs dig to find the truth about how a recent shootout at a gun store might connect to a young woman who may have committed suicide.

While Catherine helps perform surveillance on a pair of meth dealers in a casino hotel room, Archie accidentally stumbles on the dead body of a casino hospitality employee in the loading docks.

The crime lab reluctantly brings in imprisoned serial killer Nate Haskell after he claims to know the identity of "Dr. Jeckyll." Meanwhile, clues revealing his next and perhaps final victim are mailed to Dr. Langston.

The CSI team investigates a well-orchestrated bombing at the funeral of Officer Franklin Clark.

A "vampire" is found decapitated in a park, and the team soon uncovers a possible alliance between his fellow vampires and a gang of "werewolves."

The death of a casino hotel guest is tied to an unlikely sexual encounter with a married woman in the room next to his, and a cat and a parrot may hold the clues of their owners' apparent double homicide.

A prostitute is found dead at the same site where a staged photo of the same dead person was taken and posted on a website days earlier, and Hodges theorizes that the parts on his new motorbike were in a fatal accident.

Dr. Langston confronts Nate Haskell one more time during his murder trial. Meanwhile, Nick faces an old teenage nemesis, Jason McCann, who is seeking revenge for his brother's death.

After a cop convicted of killing his police officer wife is killed in prison, the team discovers that he may have been framed, and Brass and Vartann may have been romantically linked to his wife.

The CSI crew is stumped when they discover a disembodied brain at a crime scene where all the other brains are accounted for.

When the CSI team investigates three seemingly unrelated murders, they discover someone is getting revenge for cold case murders that were never solved.

The skeletal remains of three people are found in the desert. Initially beetle evidence implies they had been dead at least a week but other factors contradict that. They bodies were identified as a lawyer, that Catherine had a connection with, and his two employees. Catherine had recommended the lawyer to a friend, who was trying to escape her dangerous husband. After analysis the beetles appear to be genetically altered. Catherine fears her friend could be dead until she makes contact with a location.

D.B. turns to a "blood whisperer" from his past to help solve a crime involving a gunshot victim who has lost his short-term memory.

A vehicle explodes during an off-road race, and the team discovers that it may have been connected to a plot to kill an oil executive.

The team must figure out who killed a television news anchor on the set during a blackout.