The team receives a call about a murdered Marine, Lt. Michael Torres who is found beaten to death in an alley downtown. They head to Torres' apartment after they are informed of a break in and find Captain Joe Wescott there. They question Wescott who explains he was gathering supplies at Torres' apartment to hunt down the multiple attackers that went after he and Torres. Surveillance video from the alley is compromised as "ghost images" of people from previous recordings appear on the VHS tape. Abby's wound analysis concludes that there were two attackers that night, which prompts Gibbs to confront Wescott about the inconsistencies in his story. Wescott is outraged at his accusation and Gibbs takes note of his disturbed behavior as well as the letters "I-J-I" found in Wescott's notebook. After re-assembling the footage from the alley, the team is able to discern just one other man with Wescott and Torres that night. Facial recognition software identifies the other man as Randall Kersey and the recovered footage also shows that he was the one being attacked. Abby examines particles underneath Torres' fingernails to determine they were fibers from Wescott's jacket and that Torres had been holding him back. Kersey is brought in for questioning and tells Gibbs that when Wescott started attacking him at random, Torres tried to break them apart and suffered a fatal head wound when he hit the ground. They track Wescott down and Gibbs is able to break through to him, understanding that he is suffering from PTSD. Wescott tells Gibbs that he attacked Kersey thinking he was fighting in the war and Gibbs has Wescott speak to a doctor about his PTSD. Tony links the letters Gibbs found to the Ijil Rebels responsible for the ambush against Wescott's unit in the war. CIA surveillance footage from the ambush reveals Robert Kersey as a member of the Ijil Rebels. The team heads to Kersey apartment only to find it empty, except for the large amount of bomb-making materials...to be continued.