After an emotional NCIS episode last week, the show is off tomorrow night due to U.S. presidential election coverage. Perhaps appropriately, its return next Tuesday is the first of two episodes devoted to PTSD!

When a Navy 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 (guest star Brad Beyer).

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, in part one of "Shell Shock," a two-part episode.

Watch CBS' first teaser for the installment below and see what you think:

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.