In the episode, Willows helps the CSI team with a cold case that has remained unsolved for the past 14 years. Helgenberger will appear in flashback scenes as well as the present day.
“We will flash back 14 years to seminal moments that show Catherine, Nick, Sara, Greg and Ecklie as they were, [and how that] informed the evolution of the characters now,” said executive producer Don McGill. “It’s going to be a really fun episode, very emotional, that honors 14 years of CSI.”
By joining the list of TV shows that have aired 300 episodes -- Bonanza, Ozzie & Harriet, The Simpsons -- CSI has put itself in elite company.
“We’re in almost every country except North Korea,” said executive producer Carol Mendelsohn. “There are just two or three countries that don’t carry CSI.”
Mendelsohn is glad to have Helgenberger back on the program after she left in January 2012. “She was really excited,” Mendelsohn said. “She was excited to come back.”
Producers were unable to get the show’s original leading man, William Petersen, to return. “Billy is so sick of hearing Don and I asking him to participate. We never stop,” Mendelsohn said. “He was actually on stage in Chicago in a Steppenwolf production when we were filming the last episode.”
As a treat for fans, McGill and Mendelsohn have added the number 300 to the episode and it will appear 14 times, once for each season of the show.