Grissom suspects murder, not suicide, when the body of a dwarf is found hanging from a rope high above a stage in a casino hotel where a convention of little people is being held. Across town, Catherine is attacked at a crime scene where a man was murdered during what appears to have been a home robbery.

A middleweight boxing champ dies in the ring after taking a brutal beating from his nemesis, but Grissom finds evidence that points to murder. Outside, in a nearby parking lot, Catherine works a crime scene where a Los Angeles gang member was gunned down, apparently by a rival gang. Also, Nick investigates a jewelry-store robbery.

Grissom, Warrick, and Nick investigate the case of man who apparently was murdered and pushed off a six story building. Grissom's involvement is cut short by renewed hearing problems. Catherine looks into the murder of man outside of his regular bar.

Warrick investigates the drive by murder of a young girl in his old neighborhood. The girl's father is a friend and mentor of Warrick's as well. Warrick struggles to control his emotions to the point where Grissom pulls him off of the case. Nick tackles the murder of a computer company employee. The only supects are the three other employees in the building.

Catherine, Nick, and Sara investigate a seemingly months old body found in the mountains. Discovery of the man's identity lead the team to the world of robot wars. Warrick and Grissom look into the case of a man found murdered in an alley. Complicating their efforts, the medical examiner ""lost"" the body for 11 days. Greg helps this case by doing some undercover work.

A woman's body is discovered in a small press box at a high-school football field, apparently the victim of strangulation. The evidence leads investigators to two convicts, one of whom is still in prison. At the crime lab, an explosion destroys key evidence and leaves Greg and Sara injured.

Grissom and Warrick get the case of an old woman found mummified in her closet. Sarah and Nick arrive to investigate a breaking and entering to find a raped teen. These cases are not as disparate as they first seem. Catherine looks into a gun found by a boy. The gun is connected to a week old murder across town that Warrick caught.

A severed head is shipped to Dr. Robbins from Jackpot, Nevada. Grissom goes to Jackpot to find the rest of the body and gets very little cooperation from the locals. Catherine gets an unexpected gift from her father.

A robbery at a grocery store results in a shootout leaving five dead. The police officer at the scene believes Grissom has a grudge against him. The entire team has to process the enormous amount of evidence at the scene.

Heavy rains in Vegas wash up a body in the storm drains. As the team investigates, they find bones from another murder.

Grissom and Sara investigate the murder of a woman after a swap party. The married couples in the neighborhood meet and switch partners. With the help of a crime scene cleaner, Nick and Warrick find there was more to their crime scene than they first thought. Catherine wants a promotion to day shift supervisor.

Grissom is called to a murder of a 17-year-old in a casino penthouse. Sophia Curtis (Louise Lombard) joins him in his research, she normally works in the day-shift. The entire team gets involved when its discovered that a kiddnapping took place along with the murder.

The CSIs investigate the stabbing of a motocross racer who was about to leave town with a young woman he had been living with. Also, Nick comes closer to finding the truth about his kidnapping.

The CSIs must investigate when a party girl is injured and killed in a traffic accident.

A man accused of murdering his wife and co-workers leads the CSIs on a wild ride through a busy casino, eventually barricading himself and a hostage in a casino hotel room. The CSIs process the evidence from the crime scene to determine whether or not the man acted alone or had an accomplice. One of the CSIs eventually steps in as a hostage negotiator, putting himself in danger.

While investigating an elderly woman's murder, Grissom receives a miniature crime scene replica; Greg attends a hearing to ascertain his culpability in a teenager's accidental death.

The team has a hard time trying to understand Michael who has become a team member since Grissom’s teaching hiatus. They investigate the murder of an unidentified girl who may have been killed by a serial killer who has been killing since the early 1970’s.

Once he unseals a package sent to him through the mail, Grissom is floored when he finds a miniature crime scene inside. The finding is entirely more perplexing since the successive killer accountable for earlier related miniature crimes is now deceased. Grissom plows to examine the miniature and discover the actual location, when the investigation makes it clear the murder showed has yet to happen, but is probably going to happen soon.

The CSI labrats take center stage to discuss the case of the Miniature Killer.

As the CSI's continue their search for and discover the identity of the "Miniature Killer", Grissom and Sara's relationship gets exposed to the rest of the team as she goes missing during the investigation. The "Miniature Killer" is finally captured, but not before a member of CSI becomes the killer's final victim.

With time, the weather, and the desert against them, the CSI team must work together to find Sara before she dies from the miniature killer's attack.

Grissom and the team join forces with Jack Malone, an FBI Agent from New York to track a serial killer.

The crossover continues on Without A Trace S06E06 Where & Why (II).

Hodges stages hypothetical murders in the lab in order to give his fellow lab techs a chance to play CSI, but unbenownst to them he has other motives behind his actions. Meanwhile, after Sara's farewell, everyone tries to comfort Grissom.

Brass, Catherine, Grissom and Nick work the case of a female victim found in an apartment building with a gun shot wound. Drops becomes a person of interest during the investigation, even though he is still in jail.

The murder of a mother and her child seems to be connected to a murder case from 12 years earlier.

When the team discovers a connection between a new murder and a serial killer, Grissom secretly joins the class of a criminal pathologist (Laurence Fishburne) to help crack the case.

The CSI team is shocked and saddened when, after working with Dr. Raymond Langston (Fishburne) on the "Dick & Jane" murders, Grissom announces that his time as a CSI has come to an end and offers Langston a permanent position on the CSI team.

Langston is shocked when his former student is found murdered and becomes the focus of a CSI investigation into the world of Mexican wrestling.

When the producer of the reboot of a classic SF show is murdered at a Las Vegas science-fiction convention attended by both Hodges and Wendy (both, unknown to each other, fans of the original show), they find a connection with each other as the team investigates the crime.

A cache of missing chips from a closed down casino turn up in Vegas and a string of murders follow, leading Langston to use deadly force for the first time in his career as a CSI.

A rising young star is killed in a wreck and her determined stalker claims credit, but the team finds out there's more to this tragedy than meets the eye.

The team investigates the murder of Jason, a troubled computer geek working at a low-level casino support industry job who lures a colleague, Paulie, into a dangerous plan to make a working stiff's dream come true.

When Hodges and Wendy take a group of high school CSI Explorer Scouts on a field trip, they embellish their role in solving cases and take their assignment a little bit too far.

The CSI's lives are on the line as they close in on the elusive Dr. Jekyll, and more than one member of the team may not live to see his capture, on part two of a two-part 10th season finale of CSI.