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.

A bomb goes off in an office building killing one and injuring many more. The chief suspect is a security guard who left minutes before the explosion and has knowledge in bomb making. Nick helps his prostitute friend again. After giving in to his passion, she is found dead the next morning. Naturally, Nick is a suspect and to make it worse, Ecklie has the case.

On the day Grissom has to evaluate his team, a head is found in the trunk of a car. While Gil and Catherine work on the head, Sara and Nick investigate a body in the desert that's missing it's head. Warrick looks into a murder in juvenile detention in which his young friend James is the only witness.

The entire CSI team investigates a disappearance at a local university. A young woman vanished, seemingly off the face of the earth.

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.

Grissom investigates the murder of a Las Vegas photographer whose remains were dumped at a nearby body farm where CSIs routinely study corpses, and his findings reveal that the man was apparently shot to death even though there are no bullet fragments in the body.

Grissom investigates the murders of four monks who were shot point blank while chanting in a Buddhist temple; Catherine reopens a cold case in which her best friend was murdered, after the man convicted of the crime claims he's innocent shortly before he dies.

Grissom and Sara investigate when a man's body, which has been doused with lye, is found buried in a park; Nick tries to determine how a hiker apparently drowned in a desert.

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.

Fifteen years ago, Catherine helped put John Mathers on death row for the rape and murder of a coed at a nearby college. Her body was dumped in a trash bag, and two other girls found the same way were also linked to the suspect. As the episode opens, Mathers is about to be executed when he's granted a stay based on new DNA evidence. But while Catherine awaits the results of tests on hair samples found on the first victim, another girl at the same school is murdered... and discarded just like the first three - meaning the wrong man could be behind bars.

Catherine called in by a pornographic-film developer to view graphic footage from a snuff movie in which a woman is brutally slain. But the clues are scant: The murderer isn't clearly seen, the cheap-looking hotel room could be almost anywhere and the film was sent to the developer anonymously. Outside of town, Grissom investigates another killing when a body, smothered with fire ants, is found stuffed inside a large toolbox. The initial findings indicate that the person died well over a year earlier.

Some bird watchers find a raven with a human eyeball in its beak. This eventually leads our CSIs to a divorced man and his 2 children but not much else. Warrick and Grissom look into the circumstances of David's unusual and first autopsy. This takes them to a car dealership where the man worked.

A man driving with a wooden stake in his head dies in front of a casino. Grissom and Nick work to discover the 'vampire' killer. Warrick and Catherine hunt for the killer of a NBA star's 5 year old son.

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.

During Vegas's latest Heat wave of triple digit temperatures, Gil and Catherine investigate a baby locked in a car. Warrick investigates a man dead of an apparent heat stroke in his house. Nick and Sarah investigate a woman's body found floating in the lake with a blow to the head.

A suspect's infatuation with Catherine results in her taking over a high profile case. The case is a missing woman who aspired to be a showgirl. Sara and Nick are angered since it takes the career making case away from them.

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.

Catherine and Sara deal with the death of what at first seems to be a transvestite. Later during autopsy they find out that the make-up he seemed to be wearing was actually facepaint, he was a clown. Grissom, Nick, and Warrick deal with the death of a man in a homeless area. They found out he worked in a recovery center for drug users.

Grissom, Catherine and Nick investigate the death of a runner during a competition. Meanwhile Sara and Warrick investigate the death of couple in a hotel room, initially thought to be a murder-suicide. Both cases take place during this 'cop' competition , with more than 20.000 attendants (all of them cops). This gives the investigations an interesting turn, as almost all the suspects and all dead people are cops.

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

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

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.

Greg, for his final proficiency, has to determine how the Sherlock Holmes of a Sherlock Holmes club was killed. Nick and Warrick try to determine how the driver of jeep was killed when the car ran off the road. They have to do this under budget while Catherine is watched by Ecklie.

Grissom, Sofia, Sara and Greg investigate the disappearance of a woman coming home from a night out with a friend, her abandoned car found on the edge of a highway. Catherine, Warrick and Nick investigate the deaths of a hunter and his prey, a Kodiak bear.

Grissom, Sara, and Nick investigate a wildfire that killed one man and badly burned a woman. Catherine, Nick, and Warrick get the case of a family of three murdered in their home.

A man (Alan Rosenberg) whom Catherine flirted with at a bar reappears in her life as a suspect in a murder investigation.

An up-and-coming movie star is found dead in his hotel room after a night of partying with his groupies.

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.

The CSI team investigates the murder of a man suffering from a congenital hypertrichosis, causing him to grow excessive body hair. Elements of the case suggest a connection with a belief in werewolves. The case leads to the victim's sister, who suffers from the same disease. Because of her condition, she'd been hiding from the world, but it turns out that she's hiding facts that are vital to solving the case.

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

The CSIs become the focus of a reality TV series, which follows them while they investigate a serial rapist, who recently gained access to a woman's apartment by posing as a fireman. Also, Warrick's work on the late-shift is causing problems with his marriage to Tina.

A wealthy defense attorney is killed at her son’s wedding but Nick’s car, containing all the collected evidence is stolen and the case is compromised. After discovering new evidence, the team suspects that someone from the wedding party may be responsible for the murder.

In the season finale, the CSIs wait by the bedside of one of their own when he's shot in the line of duty. One CSI faces a hard choice by having the power of attorney over their injured friend and colleague. Meanwhile, the team also investigates the strange way of life of one man when he is found decapitated by a train.

In part one of this two-part seventh season opener Grissom and Catherine handle the case of a women's dead body found at Cirque du Soleil by a performer. Meanwhile, an investor at one of Sam Braun's new casinos is shot to death during a party on the rooftop. Catherine's life is in jeopardy after visiting a nightclub with Nick. Grissom finds a miniature replica of a crime scene that he is investigating.

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.

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.

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

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.

Sara questions her future as a CSI when a past case comes back to haunt her, the 12 year old Hannah, who has to back up her brother one more time with all new tricks up her sleeves.

CSI investigates the death of a little girl whose identity remains unknown.

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

After several victims are found dead while performing normal, everyday activities, the CSIs must find the reason as to why each of the victims remain upright after dying.

Grissom asks Lady Heather for help when the team investigates a case connected to the world of domination.

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 detectives search for the murderer of FBI agent Billy Ray Jackson, only Billy Ray isn't really an FBI agent, and neither are his impressively capable partners, Miles Baker and Emma Solomon.

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.

When Nick, Greg and Hodges take Henry to celebrate his birthday at a biker bar, they uncover a double homicide and find several suspects still at the bar who may be the murderers.

When a band member of Rascal Flatts is electrocuted by his own guitar during a concert, the CSI team investigates if it was a case of foul play.