"Shell Shock (Part I)" is the sixth episode of the tenth season of the American police procedural drama NCIS, and the 216th episode overall. It originally aired on CBS in the United States on November 13, 2012. The episode is written by Nichole Mirante-Matthews and directed by Leslie Libman, and was seen by 17.05 million viewers.
When a Marine Lieutenant who recently returned home from the Middle East is found dead from a brutal attack, the NCIS team questions the victim’s friend, Marine Captain Joe Wescott. Gibbs realizes the Captain is suffering from post-traumatic stress disorder, but knows his experience overseas may also provide a key link to the crime.
The plot continues in "Shell Shock (Part II)".