After fifteen seasons and three spin-offs, one of which, CSI Cyber, is currently running, CSI wraps up its series of stories set in Las Vegas by airing a grand finale. It’s a way to reunite and say goodbye to all the characters who have embodied the scientific spirit of the police procedural drama, starting with William Petersen in the role of Gil Grissom, the legendary nightshift supervisor of the unit who quit during the ninth season and left the office in the hands of Dr. Raymond Langston (Laurence Fishburne).

Immortality starts off with a suicide bomber who blows himself up in the casino owned by Special Agent Catherine Willows, who rushes back from Los Angeles to run the investigation. Meanwhile, Gil Grissom gets arrested for trespassing in the port of San Diego, and D. B. Russel offers Sara Sidle the chance to take over the investigation into the bombing attack.

"When I was writing the pilot, I wasn’t really aware of the success of the show; the mandate was to break every rule in television, write something visceral and have a new take on crime drama. And of course put in the forensic science that people didn’t know about in 2000. In 2015, we did the opposite - there was far more character, we went to some old-school, regular science, and it was much easier in my opinion than the pilot because, although I wrote the pilot in 3 days and wrote the two-hour (finale) in 7 days, the characters were well established, the voices were clear, the actors were back, so I felt like I was a typist." [Anthony E. Zuiker]

"This movie happened very fast. We didn’t have much time to really cogitate about it. They put us in a little bit of bind, cramming it together and getting it done. But that’s appropriate because that’s how it was when we first created the drama in the first place. Nobody had a template for it. It wasn’t one of those shows from Aaron Sorkin or David Chase where someone had been thinking about this for 10 years and knew exactly how they wanted it to be. Creator Anthony Zuiker had never done TV before. Even [then CBS Entertainment president and now CBS Corp. chairman] Les Moonves was like, ‘I don’t get it, you are going to dust for fingerprints? That’s the show?’ [...] It was the right idea, at the right time, with the right people, at the right place and we weren’t bothered by anybody. The network left us alone because they didn’t think it would be much of a deal. They put us on at 9 on Friday nights. Nobody really knew what we were doing." [William Petersen]