A murder appears to be a suicide with very little evidence.

Grissom, Sara and Warrick investigate the apparent hit and run of a young man...they soon discover he was deaf. Meanwhile, Nick and Catherine are attempting to solve a mass murder in a coffee shop.

Catherine gets emotionally involved while investigating the death of a six-year old girl at a carnival. Grissom, Nick and Warick take on the case of a jogger who was apparently attacked by an animal who knows how to use a scalpel.

A head is found in the trunk of a car.

An old lady is found dead with a stab wound in her chest. There are over 20 cats in her house.

Grissom and Sidle investigate the death of someone who was buried in a shallow grave in a park and covered in lye. The autopsy reveals that the victim was struck by a car in the last 72 hours and bled to death. There was no blood at the grave site, however. The accident is traced to a young lawyer who has just started as an associate with a major law firm. Stokes looks into the death of Stacy Warner who is found in the middle of the desert but is determined to have drowned. She was a an extreme sports enthusiast out on a challenging trek but she seemed ill-prepared for the route she took.

Las Vegas's retired police commissioner Duke Rittle was tortured to death after an 'exclusive' party. The ex-con who drove him is found murdered in the car's trunk, but not the last on Grissom's trail. Rittle's young daughter Sasha is missing and the suspect, a socialite chameleon, is seen on a private flight to Miami. Grissom sends Catherine there. Luckily Lieutenant Horatio Caine of the Miami CSI team takes brilliant charge, realizing it's the MO of a Florida serial killer of socialite couples, who spared the girl but eliminated all other witnesses and clearly isn't done yet, even sets a trap for the police.

Boxer LaRoi Steele didn't survive his third fight against Javier Molina, whom he defeated in both earlier encounters. Grissom works out what happened exactly and why after learning how that Vegas show discipline really works. Nick wanted a solo case but isn't tickled-pink with a jewelry theft, yet does it well enough to counter abuse from ingrate victims. A gang fight involving an arrogant 'modern' gangster turns out to tie in as well.

A taxi driver accidentally runs over a teenage boy. He is later brutally beaten by a gang who thinks he is running away. Grissom and Sara works on the case and finds that the boy was dead prior to being hit from a stab wound.

A man driving with a wooden stake in his head dies in front of a casino.

An elderly lady drives her car recklessly into a café for no apparent reason. Meanwhile, a wife dies of carbon monoxide poisoning while her husband does not even though he was sleeping right next to her.

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.

There is a heist in a supermarket with five casualties, including police officer Clay. The entire CSI team investigates the case. Officer Fromansky, Grissom's longtime foe and who killed the robbers and a civilian, claims that there was a third robber on the scene. However, the evidences do not corroborate with his testimony. The CSI proceed the investigation and conclude also that it was an inside job. Will they find the truth?

Although living in a well-protected gated community, the couple Mike and Laurel Trent are executed in front of their house by two masked killers. They were owners of the famous Acid Drop club among other properties. Grissom notes that Laurel was dragged out of the car, but Mike was dragged down the driveway in a place where everyone could see him. The whole team is assigned to investigate the case since the real state is large. Soon they find that the jewels have been robbed and Laurel had made porn films in the past with the production of Drake the Snake. Catherine goes to the Acid Drop and interviews the manager Chris Bezich first and Drake, who is bartender, later. Their further investigation shows that Mike's former partner Kyle Goode is suing him in the justice. When Grissom is summed to a murder case in an apartment, he finds evidences that will help him to resolve the case.

The body of a young gambler is left at a neon graveyard. He died from two gunshots to the back of his head. Prior to his death, he won a lot of money from one of Sam Braun's casinos. This makes Grissom remove Catherine from the case.

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.

When a corpse is found in a storm drain gate, Grissom, Warrick and Catherine investigate the case. Warrick and Catherine follow the storm drain and find that the victim is the lifeguard Calvin Berkowitz and they believe he died "surfing" during the rainstorm. When they leave the place, a sewage worker shows some bones they have found while working. Soon they learn that other bones were found in the sewage drain and try to find the point of origin, while they also research the missing persons database. Capt. Brass talks to a resident of the neighborhood and he complains of a bully teenager, Owen Durbin. Soon his family becomes the prime suspect of the case.

While in a dinner party to celebrate the retirement of Director of Robert Cavallo and the promotion of Conrad Ecklie, Grissom is summoned by Capt. Brass to investigation a homicide in the Olympia Hotel. He stumbles upon Ecklie's right hand Sofia Curtis in the elevator and they go with Brass to the suite where they see the body of the teenage Nicole Jensen next to vomit. Soon they learn that the suite was reserved by the hotel's owner Charlie Macklin for his daughter Janelle. The McKinley High School is giving a homecoming party in the ballroom, but Janelle is giving a private party in the suite. Catherine, Nick and Warrick join the investigation and interview the guests. They note that Janelle is missing and they learn that two masked kidnappers have abducted Janelle. When Catherien and Sheriff Atwater interview Charlie, he tells them that he knows his daughter and that was a prank to get his attention. The CSI team proceeds the investigation and find the truth of what happened during the night.

When the young mother Lori Kyman is reported missing by her husband, Grissom and Sofia meets with Capt. Brass on the highway where her car was found with flat tire. Sara and Capt. Brass go to Lori's house to interview her husband Mark, and they find her best friend Amy Maynard. Lori's stepmother Diane Hoyt arrives and confirms Mark's alibi. Soon Greg finds that the valve of the flat tire in Lori's car was unscrewed leaking the air, and he finds prints. Meanwhile, Catherine, Warrick and Nick investigate the deaths of the hunter Rod Hollis with claws around his neck and a Kodiak bear in the woods. However, the animal is not native from the area. In the autopsy, Dr. Robbins finds that bear was shot twice, by Hollis' rifle and by a Magnum .357 that was used in a robbery and belongs to Aaron Colite. A microchip in the bear shows that he belonged to Clark County Zoo and was bought by a broker.

When the wealthy casino owner Bruce Eiger is found dead on the front steps of his mansion, Ecklie assigns the entire team to the case. They investigate whether Bruce has jumped, felt or was pushed off the second floor. In the autopsy, Dr. Robbins finds that Bruce was sodomite, with repeated insertions into his rectum. When they find a secret compartment in Bruce's mansion, they are forced to understand the bizarre world of Infantilism.

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.

When the flight attendant Martha Krell is found dead and raped in her hotel room, Grissom, Greg, Sara and Capt. Brass investigate the case. They note that there is no luggage in the room that was cleaned and sanitized without any evidence. Ecklie tells Sara that he had a similar case five years ago, with the flight attendant Sue Stein. Sara notes that the present technology is able to retrieve the fingerprint from the previous case. Meanwhile, Catherine, Nick, Warrick and Det. Chris Cavaliere investigate the case of the death of the twelve-year-old Ty Hawkins, who has been beaten to death on his bed while sleeping. His fourteen-year-old brother Matt becomes the prime suspect to Det. Cavaliere and when Matt confesses the murder of his brother, Nick questions the way Det. Cavaliere conducted the interrogation. The CSI team proceeds the investigation and finds two other suspects: Ty's father Martin and the homeless Walter. Who might be the murderer?

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.

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.

A half-naked woman is found half buried in the desert with a branding on her arm. She has no hair and is missing her right hand. The woman turns out to be Lady Heather's estranged daughter. The autopsy reveals that the woman was a victim of an experiment and starved to death. The team investigates the Betz Clinic where the deceased underwent a sleep therapy session for her insomnia.

While Jim Brass is in surgery the team has two cases to tackle. The first involves a man, found decapitated on train tracks, with a 19-inch waist. Further investigation reveals that he wore a wasp corset, as was fashionable with gentlemen during the Civil War. The other crime scene is in a hotel room where a man is found in his boxers, dead, on the bed. Scattered around the room are evidence of a wild night of alcohol, drugs, and sex. Ellie, Brass's estranged daughter, comes to visit her father from LA.

A pedophile arsonist maintains his innocence in the disappearance of two young boys, but he is also willing to help the investigation by giving Grissom insight on the potential kidnapper's mindset.

When one Trenton cop is murdered in Las Vegas, a second threatens to expose Keppler's past if he doesn't make the case and the evidence go away.

A mobster that Warrick had a run-in with is found dead, and Warrick is found at the scene with the murder weapon. However, he insists that he has no recollection of the crime.

CSIs past and present come together at the news of Warrick's death. But will Warrick's real killer successfully frame another police officer for his murder?

A biker who is brutally stabbed to death in a biker bar turns out to be an undercover agent whose cover was blown.

A mild-mannered operations support employee kills one of his co-workers. But while CSI is busy trying to figure out the killer's identity, the motive for his crime is revealed.

When a police officer shoots and kills his ex-partner in a parking lot, the team must figure out whether it was premeditated and possibly racially motivated.

After finding a new dead body, Langston and Brass uncover a connection to an unlicensed doctor who may be "Dr. Jekyll." Meanwhile, Willows discovers that two women found dead in a hotel were con women who preyed on an unsuspecting actuary.

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.

Hodges and Wendy pose as CSIs to impress a group of "Crime Cadets" and get some help in solving a crime, and Hodges becomes jealous when Henry asks Wendy out. Meanwhile, Nick and Greg solve a bacteria outbreak at the police station.

A shark attacks a woman in the pool at a casino day-club, and Catherine soon suspects it's part of a feud between rival casino owners. Meanwhile, Wendy has some sad news for Hodges.

When two people who were thought to be dead come back to life, the evidence leads CSI back to a discredited ex-professor who conducted bizarre death-related experiments in the 1970s.

Dr. Langston kills Nate Haskell, but was it murder or self-defense. Meanwhile, a closer look at the crime scene reveals details about Haskell's twisted past and his descent into a serial killer.

The task of solving the grisly quadruple homicide of an entire family becomes more complicated when three people confess to the crime.

CSI investigates a massacre at a local diner, and the team suspects that one of the victims' stalkers is the shooter.

CSI investigates a homicide involving a victim found in a human-sized hamster ball, and Brody gets some help as she tries to find a serial rapist.

The CSI team investigates the murder of a young victim dressed as a superhero.