Set against the flashy backdrop of Las Vegas, CSI: Crime Scene Investigation follows a smart, good-looking crime lab crew as they use science and technology to solve the city's most gruesome crimes. Most episodes begin shortly before a victim is found dead, giving viewers a hint of what happened before the crime lab gets involved. Then the steel-stomached investigators arrive: Brainy, bug-obsessed Gil Grissom (William Petersen) is the original head of the team; former exotic dancer and single mother Catherine Willows (Marg Helgenberger) began the series as a supervisor and took over as boss when Grissom retired; and Warrick Brown (Gary Dourdan), Nick Stokes (George Eads), and Sara Sidle (Jorja Fox), Greg Sanders (Eric Szmanda) round out the rest of the cast. Rubber gloves, cotton swabs, fingerprint lifters, and keen senses play key roles in the initial evidence collection. Back at the lab, the crew tries to reconstruct the crime scene, testing theories against the evidence until the truth is revealed.