A world-famous poker champion drops dead in the middle of a game. He appears to have had a heart attack. Outside of the city, Nick and Catherine investigate the death of a young street racer.

Hollywood sex symbol Tom Haviland admits having had sex with a girl who is found in the same casino hotel, throat fatally pierced with a corkscrew. As he failed to clean up, the team quickly gathers enough evidence for a murder charge. His top lawyer chooses to demand a near-instant trial, leaving CSI almost no time to work out the part of Tom's buddy and a second victim, actually the first murder. Meanwhile Grissom's mentor and predecessor, Dr. Phillip Gerard, uses all his forensic expertise to question every move they make and discredit team members.

The owners of a house placed on sale are found dead, their bodies discovered by two interested buyers. Sara is working solo on the death of a cheerleader at a high school.

A dwarf is found dead, hanged in an auditorium during an annual convention for little people. Working on a case of murder during a home invasion, Catherine is attacked by the perpetrator while processing the scene.

During a magic show, a female participant really disappears during a disappearing act. Nick and Catherine investigates the death of a rock star found on his tour bus with a needle stuck in his arm.

On the day of convicted serial killer-rapist John Mathers's execution, a new case following his MO causes a stay after countering the already administered lethal injection and urgent forensic (re-)examination. It was Catherine's first case leading to death row. The most modern techniques, even requiring federal equipment not available to Greg, show another killer was at work and probably one was a copy-cat, but the question remains in which order, as that may or not discharge Mathers.

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 murder is caught on tape. With no body or a crime scene, Sara, Warrick and Catherine must get as much information as possible from the grainy 16 mm film. Grissom and Nick must brave a colony of fire ants to recover a body.

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 body falls out of the sky, literally. The cause of death is suffocation but the body bears no signs of strangulation.

When the supervisor of a meat-grinding facility finds a hand in a grinder, Grissom, Catherine and Capt. Brass investigate the case. Grissom is able to take the finger print of the hand and learns that the body is from a chef of the five stars restaurant Debreef. Grissom and Catherine head to the kitchen of the restaurant, where they find a team tied by a code. Meanwhile, Warrick and Sara investigate the apparent suicide of a bipolar woman. They learn that she was a very violent person when stopped using lithium and hated by many people. They suspect she might have been murdered in accordance with the crime scene..

When a group of bird watchers sees a raven with an eyeball in its nest, the CSI team investigate the case. They trace a radius from the nest and using the evidences, they find the location where the corpse may have been dumped. Catherine, Sara, Nick and Capt. Brass find the body and they identify the body. The prime suspect is the ex-husband of the victim. Meanwhile, Grissom, Warrick and Dr. Robbins find that the car seller Fred Stearns is not dead but dies later. They suspect that one of his colleagues may have killed him.

Matt Phelps sends his two kids to bed, and out of the blue, there is a drive-by shooting and his daughter Aimee is shot and killed in her bed. Grissom, Warrick and Capt. Brass investigate the case and Grissom learns that Matt Phelps is Warrick's mentor and friend. Warrick's investigation is conducted based on his emotions instead of on the evidences with serious consequences for Matt and a suspect. Meanwhile, Nick and Sam Vega investigate the mysterious death of a boss of a four-men Internet service company in the air-conditioned servers' room. They find many secrets in the team but no suspect and no murder weapon. Until Nick observes the duct of the air-conditioning.

When Joanne Crooks is assaulted without rape at home, Catherine, Grissom, Nick, Warrick and Capt. Brass assume the investigation. They find fingerprints on the windows and they learn that the criminal is escalating in his crimes. They fear that he soon will rape his victim since this was his first break in. Meanwhile, Sara learns that the paraplegic prosecutor Melissa Winters will be submitted to a surgery of high risk. Three years ago, Winters was shot on the neck in a home invasion where her husband as killed, but the murderer has not been found. Now the bullet has moved and she needs the surgery. Sara decides to reopen the cold case using the bullet withdrawn in the surgery to try to find the criminal.

When a body is found in a foam party, he is identified by Grissom and Capt. Brass as the male prostitute Trey Buckman. Meanwhile, Catherine and Nick investigate a decomposed body of the also male prostitute Croix Richards in his apartment. Catherine receives a phone call from Eddie's phone, who is with Lindsey, with poor reception, but soon she learns that Lindsey is screaming and she leaves the crime scene to seek out her daughter. She finds Lindsey in a car in the water but she rescues her. Sara and Det. Vega investigate the case and they suspect that Eddie is dead. Meanwhile Grissom concludes that both victims may have been dead by insulin and they were employees of Lady Heather. Grissom and Catherine visit the suspect Rebecca and meet her husband Steven McCormick that tells to them a weird story. Then he goes with Capt. Brass to Lady Heather's house. Grissom has a personal moment with Lady Heather and when he learns that she is diabetic, he requests a warranty to get her insulin.

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.

A really badly decomposed body of a man is found in a chemical waste barrel. The markings on the barrel indicates that it came from a warehouse, now used as an arena for specially-built remote-controlled robots to destroy each other.

A man is found stabbed to death in an art house cinema while a young shooting victim is found in a storage room with a bizarrely wide bullet hole pattern.

While performing on the stage, the comedian Dougie Max dies. Grissom, Catherine and Capt. Brass investigate the case and Grissom and his team conclude that he was poisoned by the expensive bottled water Innoko. When a teenager dies in a convenience store, Warrick is assigned by Grissom to investigate the case, and soon he finds that the youngster had drunk Innoko water. Grissom finds that the bottles came from the same lot, and was not a tampering case. Meanwhile, Brass asks Nick to reopen the case of Shelley Stark, who died in an accident in a bathtub and Brass did not call any CSI investigator. He has just seen her husband with a hot woman driving a Ferrari and he is intrigued, since the man was inconsolable. Nick and Sara reopen the case and find new evidences.

When a private jet lands after a party, they find the trainer Lori Hutchins dead apparently stomped by the horse in the cargo bay. Grissom, Catherine, Nick and Capt. Brass investigate the case. The horse is in quarantine and the veterinarian Dr. Stevens help Catherine to collect material from the animal. They interview the owner of the jet, guests and crew and find two tranquilizers dart in the cargo bay. When the horse mysterious die, Dr. Robbins make the autopsy and they learn what happened in the flight. Meanwhile, Sara, Warrick and Det. Lockwood investigate the suicide of a teenager in the middle of the desert. When they find a second body dead in the same circumstances, they believe it was a kind of "Romeu and Juliet" pact of the younger. Then they identify the couple, Toby Wellstone and Jill Frommer, and interview her mother trying to understand why they died in a distant place and separated from each other.

A couple of high school students find the body of a woman in the press box of football field. Grissom, Nik, Sara and Capt. Brass investigate the case and they learn her identity, the waitress Alison Carpenter. Their further investigation lead them to the former prison inmate Jason Kent, who has recently been released. Alison was his girlfriend and was having sex with the drug dealer Jesus to postpone the debt of Jason with him. Meanwhile, Greg's DNA laboratory explodes and Sara and him are injured. Warrick and Catherine are assigned to investigate the case and find the responsible for the accident.

A team of robbers heist the First Monument Bank and Detective Cyrus Lockwood is shot and murdered. The team investigate the case and find that the thieves wanted a specific safety deposit box in the vault. Meanwhile the driver of the getaway van is found dead in the vehicle, Larry Whiting. He was a former valet of the Rampart Casino, owned by Sam Braun. When they find the name of the owner of the stolen box, Benny Murdock, an Catherine recognizes the name.