- Season 15 Episode 17
Immortality (Series Finale)
After "a catastrophic event paralyzes Las Vegas, Gil Grissom, Catherine Willows and Jim Brass return to help the team with the investigation. Also, D.B. Russell and Sara Sidle make decisions regarding the future of their crime-fighting careers, and Lady Heather returns, creating [conflict] between Grissom and Sidle.
Catherine, who left town to take a job with the FBI, is lured back when a federal crime is committed at one of the casinos she inherited from her father.