CSI: Crime Scene Investigation (season 13) Las Vegas ("In Vino Veritas"), Phillips heads to a high school reunion ("Dead of the Class"), and an investigation into a series of Dante's Inferno killings bring the CSIs face-to-face Black Sabbath ("Skin in the Game"), before jeopardizing the life of one investigator. In episode thirteen of the season, "CSI" staged a two-part crossover with its spin-off show "" in which Gary Sinise marked his first appearance in "CSI" and as his "CSI: NY" character Mac Taylor; cast member Ted Danson subsequently appeared in the "CSI: NY" portion of the story. Former cast member William Petersen also returned as Gil
Immortality (CSI: Crime Scene Investigation) reviewing the series finale, Gavin Hetherington of SpoilerTV named the episodes "the perfect send-off for such an epic show". He later called the episode a "dream come true" for fans of the series with the reunion of Gil, Catherine and Sara. Immortality (CSI: Crime Scene Investigation) "Immortality" is the two-hour series finale of "" aired on September 27, 2015 on CBS. When a suicide bomber detonates his vest on the floor of the Catherine Willows-owned Eclipse casino, the FBI special agent returns from Los Angeles to join the investigation. Gil Grissom, meanwhile, working to preserve sharks in international waters, is