After Warrick is shot in a Las Vegas alley, the CSI team comes together to deal with the aftermath.

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.

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.

Nick takes the lead on a case where in the house a family of four, three pools of blood are found. Nick thinks that the little girl may still be alive, but Sara is doubtful, thinking that Nick's recent near-death experience is affecting his judgement.

The CSI team says goodbye to Catherine Willows as she makes a life-changing decision.

When a teenager and her sister are the sole survivors of the gruesome murder of four members of one family in a quiet suburban neighborhood, Grissom and his entire team investigate the crime. What initially looks like a bizarre cult murder becomes more disturbing when they discover the motive behind the massacre.

Grissom returns from his sabbatical; Keppler is put into a compromising position when the bodies of a Trenton police officer and a hooker are found in a hotel room. The man who found them is a retired New Jersey cop and close friend to Keppler, who doesn't reveal their relationship.

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.

Catherine comforts Warrick when he is accused of murdering a famous Vegas gangster and even he is uncertain of his guilt or innocence.

When the CSIs are called to a murder scene at a familiar motel, Nick is thrown for a loop as he pieces together three separate murder investigations that all took place at the same establishment over the course of a year.

Grissom's nemesis, serial killer Paul Millander, reappears and claims a third victim in this gripping episode. The latest slaying matches Millander's previous killings in that it recreates his father's murder. The killer's next target was born Aug. 17, 1956...which just happens to be Grissom's birthday.

Catherine is ordered by a kidnapper to accompany a man who is to deliver $1 million in ransom to him or else he will kill the man's mistress.

Grissom investigates the murder of two men that leads him to a new encounter with Lady Heather. Catherine is desperate to find out what lead to the near death of her daughter and why her ex, Eddie, disappeared.

The CSI teams come together to save one of their own when they learn one team member has been kidnapped and buried alive, and now they must find him before he suffocates under five feet of dirt.

The CSI teams come together to save one of their own when they learn one team member has been kidnapped and buried alive, and now they must find him before he suffocates under five feet of dirt.

The CSIs sift through the overwhelming evidence from a shootout with drug dealers in order to determine who is responsible for the death of a police officer killed during the incident.

In the second part of this two-parter Grissom investigates the murder of an aging rockstar who is found dead in his kitchen with an exact replica of the crime scene on the counter next to him. Meanwhile, Catherine probes her own abduction and learns that someone may be targeting her family.

Grissom investigates when a worker at a poultry processing plant is found dead in a stun bath used to electrocute chickens before they are slaughtered. Nearby, a miniature replica of the crime scene is discovered. It's eerily similar to two other replicas left at scenes of homicides. Also, a man and a dead woman are found stuck in cement at a construction site; and an elderly Russian woman is discovered dead in her apartment with her head in a gas stove, but Warrick thinks she was murdered.

When a has-been boxer is killed, the CSIs must establish which of several life-threatening acts actually killed him.

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.

Catherine's friend Laura's mogul husband Mark has a lot to hide behind his successful international corporation, and he's hired a crack team of assassins to carry out the murders of anyone who might be aware of what he's doing, and that includes Laura's lawyer and Laura herself.

Grissom and his crew are called in to investigate the death of a young woman found in the hotel room of popular actor Tom Haviland. Haviland admits that he slept with her, but denies killing her. Grissom believes otherwise, however, after finding blood evidence on the celebrity. Then things get personal when Haviland's lawyer hires Grissom's former mentor, Philip Gerard, to find mistakes in the forensic part of the case. And, unfortunately for Grissom, Gerard finds plenty of errors to exploit.

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 casino employee is beaten and raped on her way home from work, but she survives and identifies her attacker. Unfortunately, a DNA test sets him free and Grissom must wrestle with whether evidence can ever lie. Later, Grissom comes to the rescue of a coworker who ends up on the other side of the law

The killer from The Execution of Catherine Willows returns with deadly results. The entire team is engaged in a race against time to stop this sadistic killer from succeeding again. Grissom is additionally distraught by the idea that this killer is smarter than he is.