When the CSI team is called to the Sphere Hotel to investigate a double homicide, they scour hotel’s security tapes for clues into who may be responsible for the murders. Meanwhile, Nick potentially jeopardizes the investigation by discussing specifics of the case, which later turn up on the local news -- giving the murderers insight into the investigation. Later, the team discovers another couple murdered in a similar fashion and they determine that they are looking for a serial killer.

Grissom is shocked to discover the prime suspects in his ongoing homicide investigation shot to death in their house. But what is more surprising is that their murder points to an inside job. Meanwhile, Catherine and Sara are called to investigate a college student found dead, floating in his shower.

When Grissom and Warrick arrive at a burglary scene, they are shocked to discover the mummified corpse of an elderly woman locked in a closet from a prior home invasion. Meanwhile, across town, Nick and Sara are called to a house to investigate a reported break-in. At the scene they discover eerily similar evidence to Grissom’s case and conclude that the cases are related and that both were victims of a home invasion. Also, Catherine investigates a young child who shot himself in the foot with a gun found in his yard.

As temperatures soar in Las Vegas, the CSIs investigate three heat-related concurrent cases: a dead child who was left in a car with the windows sealed, a young woman found drowned while trying to cool off at Lake Mojave and a dead couch potato who appears to have suffered heat stroke. The team must determine if the causes of death are heat or murder.

After a woman is killed in a head-on collision with a big rig, Catherine and Grissom discover, across the road, the dead body of a man dressed in a full-size raccoon costume. They uncover that the man is dressed like that because he recently attended a Plushies and Furries convention leading them to probe further into this fetish world to see who may be responsible for the man’s murder. Meanwhile, Nick and Sara investigate the murder of a convenience store employee found shot to death in the store’s industrial freezer.

Grissom’s investigation is met with skepticism from the town sheriff, who begrudgingly assists him. Meanwhile, Catherine’s corrupt father, Sam Braun, sends her a check for $250,000, which leaves her conflicted over whether to accept life-changing money for her daughter.

Warrick testifies in a rape/murder trial, but the defense gets the key piece of evidence, a bloody knife, thrown out on a technicality. CSI is given a 24-hour continuance to process the remaining "unprocessed" evidence or discover a new link tying the suspect. With further investigation, the CSIs begin to question if the suspect is actually guilty.

Catherine leads a high-profile investigation to find a model that has been missing for almost a week. After a strange 911 call, Catherine is certain she has found the perpetrator, but she must get him to tell them where the body is buried before it is too late.

When a car bomb explodes in the front entrance of a hotel on the Strip, the haunting possibility of terrorism becomes all too real. Meanwhile, Warrick and Sara are called to a hotel to investigate a powerful musician’s wife found dead in the bathtub.

The CSI investigate the murder of a teenager found at a construction site, beaten to death by multiple vicious blows from a hammer. Meanwhile, across town, Nick is called to investigate an apparent gunshot victim found shot to death in her house.

The team learns that while a group of jurors deliberated behind closed doors, one of them is found murdered, leaving 11 suspects. As they investigate the death they discover that this juror was the only one holding out on a non-guilty verdict, prolonging the trial and leaving 11 jurors with motive. Meanwhile, Nick looks for new evidence in an old murder case that is reopened after receiving new information from the eyewitness.

Grissom becomes obsessed with a victim, a woman found murdered in her home that looks just like Sara. The team then finds the disarticulated remains of their prime suspect in multiple garage cans in the area, presenting them with a double homicide that appears to be the perfect crime until the team discovers an unlikely piece of evidence left behind at the crime scene.

The CSI are called to investigate multiple homicides in the wake of a grocery store robbery gone awry. Grissom must put aside his personal animosity towards Officer Fromansky (David Andrews), who discharged his weapon after his partner was shot, in order for his team to uncover the truth behind the shooting.

The CSI team is called to an exclusive art exhibition after a rare piece from a 17th century Japanese art collection is stolen. They discover that the robbers used a decoy to distract the guests in order to pull off their heist. Meanwhile, Warrick and Catherine are called when a girl is found dead with a strange bite on her neck and missing several pints of blood. Their investigation leads them into the underground world of blood-drinking Goth devotees.

The CSI are pulled into an early morning rollout call to investigate the murder a millionaire entrepreneur and his wife who were shot to death in the driveway of their upscale, gated-community home. Grissom and his team combine their resources and discover that the victim had some shady business ventures in the past that created a few enemies along the way -- all of whom could be potential suspects. Back in the office, Grissom gives Catherine her job evaluation.

Grissom and his team are called to investigate the murder of a drug rehab counselor found stabbed to death in an alley in the wrong side of town. Meanwhile, across town at an auto graveyard, Catherine and Sara investigate the bizarre murder of a man found half-naked and dead stuffed in a tire. They discover that the victim made his living as a professional clown.

Catherine and the team find what is left of a body tied beneath the undercarriage of a prison bus and must determine whether this is an escape gone horribly awry, or murder. Meanwhile, Grissom and Warrick investigate the bloody stabbing of a man who turns out to have gambled away the life savings of his mentally retarded younger brother.

Grissom and his team investigate Walter Damian (Erik Passoja), an evil loner who dies while in police custody after beating a man to death with his bare hands. After the suspect’s death, the team makes a shocking discovery linking him to an unsolved missing person’s case.

Catherine, Warrick and Nick investigate a suburban house fire that leaves a young girl dead. The CSI team must determine if the fire was an accident or arson, while adding to the chaos is a single parent household and a grandmother suffering from Alzheimer's. Meanwhile, Grissom dives into the world of competitive "Logos," a faux gaming tournament that is a cross between scrabble and boggle, where a contestant ends up dead with an "S" tile lodged in his throat.

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.

The CSI team work together to investigate the derailment of a roller coaster at a local amusement park that results in the death of six people. They must determine if it was an accident or murder.

The bodies of two gambling cheats are discovered shot execution style, shortly after being caught scamming several of Sam Braun's casinos, making Sam the number one murder suspect. Grissom is forced to take Catherine off the case because of her biological tie to Sam.

The female victim, who barely escapes death, identifies her rapist but the DNA evidence suggests that he is not the person responsible. Meanwhile, Grissom comes to the rescue of one of the CSI members who lands on the other side of the law.