We first meet Beyer in the clip below, when it appears he's looking for his friend as well.
Gibbs realizes the Captain is suffering from post-traumatic stress disorder (Ptsd), and it's fairly obvious from the first moment he appears. Will his experience overseas provide a key link to the crime?
Check out the first sneak peek from Part I of "Shell Shock" and see what you think:
NCIS 'Shell Shock, Part I' Clip - He's Dead