A bus carrying 23 passengers from Los Angeles to Las Vegas crashes less than 40 miles from its destination, killing nine people. Tthe CSIs soon discover that a recent parolee was on the bus, but is now unaccounted for.

Jane Galloway lives in fear. Her doors are triple-locked. Every shade is drawn. The bathroom window is nailed shut. An alarm system is activated. Who killed Jane, and how could the murderer have possibly entered, and left, the house?

Grissom and Catherine investigate the stabbing death of an 80-year-old woman who lived in a run-down house full of cats; Nick and Sara comb through the remains of a car bombing that was, apparently, a murder plot gone awry.

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 handle their highest profile case to date when the city's former chief of detectives is slain execution-style in his house following a wild party. Missing from the residence are the chief's trophy wife and their 7-year-old daughter. Catherine and Warrick follow the trail to Miami, and soon enlist the help of Horatio Caine.

Season Finale. The CSIs investigate when the body of an unidentified young woman is discovered stuffed in an overturned shopping cart near a freeway underpass. Her horribly disfigured and partially decomposed face is a nightmare of blood, scabs and scars, as if she'd been shoved into a fan. A huge circular hole dominates her left cheek. Someone not only wanted her dead, Grissom reasons, but ""they wanted her ugly."" Adding to the mystery are the cart's other contents: an expensive handbag, fashion magazines and a leather day planner with notes written in code.