The CSI team investigates two unusual cases, one involving the suspicious death of a go-cart racer who took his hobby to the highway and paid the price with his life, and a murder at a hip new restaurant where patrons dine in the dark
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).
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.
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.
The team investigates an underground mob. Warrick ends up becoming the prime suspect in a murder that's related to the mob, and his addiction to pills starts to have a significant impact on his job as a CSI.
The world of illegal dog fighting is explored by Grissom and the rest of the team when they take on the case of a wealthy socialite who was murdered. Meanwhile, Warrick struggles to clear his name in the recent exotic dancer murder case.
Two murders that happen during Las Vegas' annual bull riding rodeo are investigated by the CSIs, who find that the murders might be connected to illegal bull breeding.
Grissom and his team battle the flu when they are called upon by D.D.A. Klein to investigate the deaths of several key witnesses for a grand jury case against a dangerous Las Vegas gang.
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.
A deer is illegally killed, and the person found with the body in the back of his truck apparently dressed it in a tutu. The man, who was completely drunk when arrested, was being interrogated by Nick and Brass, and suddently tries to escape and is pepper sprayed. Unfazed by the spray, officers then taser him and he bursts into flames and dies. Meanwhile an unbalanced woman wearing a tinfoil outfit at the front desk tries to warn people (including Nick) of an alien invasion. After observing the burning man, she later turns up dead with green-tinted blood. When other people turn up with the same problem, it's up to the team to figure out why. Meanwhile, an old couple dies, apparently in their sleep... but there is evidence the cases are related.
