" Blood in the Water " is the of the long-running police procedural series NCIS . Key Plot and Cast Details

(Agent Jessica Knight) officially joins the main cast as a series regular starting with this premiere.

: The episode centers on the NCIS team searching for Special Agent Leroy Jethro Gibbs after his boat, Rule 91 , was destroyed in an explosion. It is revealed he had been secretly investigating a serial killer alongside journalist Marcie Warren. Cast Changes :