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

Grissom, newly appointed head of the crime lab, investigates the supposed suicide of a jackpot-winner. Meanwhile, Warrick has to deal with the fact that the shooting of rookie CSI Holly Gribbs was due to his failure to supervise her.

The search is on for a abducted woman while a hit and run death of a little girl is investigated.

A severed leg is found in a lake while a fraternity pledge goes badly.

A young man is found naked and dead in the desert.

Department protocol is violated when Catherine investigates her ex-husband's rape accusation.

The team is called to a suburban house where the whole family, except the two daughters, have been murdered with no apparent motive.

When a man is found dead in his bathtub with a tape recorder telling that he has committed suicide, the CSI team recalls the case of Royce Harmon that was not well resolved. Grisson, Catherine and Sara investigate the case that becomes more complicated when Grisson's fingerprint is found in the scene crime. Meanwhile, Warrick and Nick investigate the case of a man that was found buckled in the back seat of his car in a dam in coma and they bet whether it was a robbery or there was a phantom driver that stole the victim.

The CSI team is summoned to investigate the death of the first-class passenger Tony Candlewell in twelve hours because of a jurisdiction problem. Candlewell has contradictory evidences of aggression and defense, and the first class passengers are secluded in the airport and interviewed. But Catherine and Brass note that they are hiding information. Meanwhile, in the autopsy, the coroner learns that Candlewell had undiagnosed encephalitis, the reason of his berserk behavior. When they find shoe prints on the back of his jacket, the passengers Lou Everitt, Max Valdez, and Dr. Kiera Behrle .are considered prime suspects. The team interviews the blind Mr. Cash that was near the incident and using dummies later, they represent the statements and come to a conclusion of the case.

Sara and Grissom investigate the death of a woman, Kaye Shelton, found wrapped in a blanket in the mountains. With no way to confirm the time of death, Grissom relies on the insects found on her body to establish a timeline. Catherine and Warrick work on a case of a stolen painting. Nick works solo on a case of a missing wife.

While investigating the disappearance of Margaret Shorey at a supermarket, Grissom and Catherine stumble upon a serial killer who claims to have killed five women in supermarkets located along the I-15. Sara and Warrick are given the case of the death of a man who, his brother claims, was killed by a burglar. Sara soon suspects that the brother is not telling the truth. Nick is specially requested to solve a case of harassment.

Grissom receives a video tape from an inmate called Frank Damon who is on trial for the arson which resulted in his wife and son's death. On the tape, Damon claims that he is innocent and asks Grissom to help him. Grissom agrees to re-examine the evidence, despite knowing that this will anger Ecklie who originally worked on the case. Nick and Catherine, meanwhile, work on the case of a young man found shot in the head inside his car.

A bomb in a brief case goes off in the lobby of an office building. The team must piece together all the parts of this bomb to look for the maker's signature. Nick becomes involved in a crime after spending a night with a woman who ends up dead the next day.

A human bone is found in the desert accidentally by a dog playing fetch with a man and his son. Grissom and Catherine assemble a team to comb the area for more bones. Back at the lab, they piece together the skeleton and determine that body was cut to pieces. From his teeth, the deceased is identified as a 70-year-old Mel Bennett. Catherine and Grissom pay a visit to his wife, who claims that her husband is at a nearby store. Sara and Warrick are called to a motel where a male stripper is found dead on the bed. The room is registered to a woman who recently threw a bachelorette party for her friend.

The team arrives at a charity fund-raiser being held at the house of Portia Richmond, an ex-show girl who became very successful, where a body is found floating in the swimming pool. Portia herself is absent from the scene. The two hosts, Patrick and Amanda Haynes, claim that she is on vacation in Europe. Warrick works on a case of a mob shooting. The deceased is found in a glass elevator with a quarter stuck in the bullet wound on his forehead.

A Jane Doe is brutally attacked and raped before being left to die on the side of the road. With two bullets lodged in her brain, she is in a deep coma. Catherine and Warrick work on an open case of a man killed by his neighbor. The statements from the accused and the deceased's wife contradict each other.

A thief is found dead from blunt force trauma to his head in a pottery store where he was evidently trying to crack a safe. The team dusts the store and finds the fingerprint of a girl who has been missing for the last 20 years. Sara and Warrick find what's left of an old woman in her rocking chair. The two believe that they are witnessing a case of spontaneous human combustion. To prove it, Sara decides to conduct an experiment by herself.

A couple walks out of a fancy restaurant to their car. They are attacked and killed. When the team arrives on the scene, the only eye-witness is a young man who stayed behind to give his statements. Catherine investigates the collapse of an apartment building which resulted in the death of three elderly people.

A kidnapping case becomes unusually personal to the usually detached Grissom. The 4-month old baby, Zach Anderson, was allegedly kidnapped from his home. A ransom note, found by his mother, is left in his crib. Many things seem strange about this case as more evidence are analyzed. When Zach's body is found on a nearby golf course, the team is sure that his death is no mere accident.

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.

There's a serial killer on the loose in Las Vegas. Since this is a very high-profile case, the sheriff brings in the FBI to help. This annoys Grissom very much as the FBIs like to assume many things while he prefers to let the evidence speak for itself. Due to his refusal to cooperate, he is taken off the case. Grissom's team, however, knows better and keeps their boss informed on the details.