Unexpected guests attend Lucas and Peyton's wedding, and Haley plays a surprise role in the ceremony; Brooke tries to keep Nick Lachey on a short leash.
After terrorists kill a state department employee and a plastic surgeon, the team searches for the only witness who can identify the killers' surgically altered faces.
The CSI team goes behind the scenes at a horror porn film studio to investigate the murder of a slasher film actress murdered on the set of one of her movies.
The team becomes immersed in the competitive world of privileged youth when a popular student at a private school is murdered.