Gil Grissom is the supervisor of the graveyard shift of Las Vegas' elite crime scene investigators. Holly Gribbs, fresh out of the academy, joins the team. Jim Brass is head of the unit and is trying to scare Gribbs from CSI. Catherine Willows, mother of a young daughter, is the number two CSI on this shift. Warrick Brown and Nick Stokes are competing to solve their 100th case to earn a promotion to CSI 3. Grissom investigates a murder staged to look like a suicide with precious little evidence. Warrick and Catherine take the case of a drunk who breaks into the house where he had been staying and is shot to death. Nick talks to a man who picked up a woman who drugged and robbed him.

A man is killed after winning a fortune and then dumping his girlfriend. So, Grissom, Nick, and newcomer to the CSI team, Sara Sidel, investigate this one. Holly Gribbs is in the hospital and Warrick is up for suspension for leaving her at the crime scene by herself. Holly later dies in the hospital, but Grissom doesn't suspend Warrick.

Grissom and Catherine investigate when a leg is found severed from a body in a lake. They suspect the husband and boyfriend. Meanwhile Sara and Nick investigate a fraternity pledging gone terribly wrong.