CBS is promising that the "CSI: Crime Scene Investigation" series finale won't disappoint.

"This will be a very satisfying ending for all the 'CSI' fans," CBS Entertainment Chairman Nina Tassler told a TV critics' meeting Monday.

"CSI," which debuted in 2000, will wrap with a two-hour finale on Sept. 27. Original cast members including William Petersen and Marg Helgenberger are returning for the send-off.

Tassler said the reunion was bittersweet. But the franchise lives on with the latest spinoff, "CSI: Cyber," which returns for its second season with Patricia Arquette and "CSI" star Ted Danson coming aboard.