CSI: CRIME SCENE INVESTIGATION 3.1 comprises 12 episodes from the third season of the forensic science drama. In this highly successful TV series, Detective Gil Grissom (William Petersen) leads the Las Vegas Police Department's night shift Crime Scene Investigations Unit, one of the top-ranked crime labs in the country. Grissom, along with his partner Catherine Willows (Marg Helgenberger), takes on a series of cases which would be untouchable by other labs, in a city with a constant influx of visitors and a series of increasingly baffling crimes.