Sitting in a Washington, D.C. office on the job talking with two possible candidates, a Marine recruiter, Gunnery Sergeant Alvarez, is brutally taken out by a single gunshot that seems to come out of nowhere. As Gibbs (MARK HARMON), Kate (SASHA ALEXANDER), and Ducky (DAVID McCALLUM) arrive at the scene, they quickly assess that a sniper would be responsible. Kate peruses the files of past candidates that would be seeking vengeance on Alvarez – who had a penchant for over-promising to new recruits.
As Abby (PAULEY PERRETTE) studies the bullet and its trajectory, she discovers that the sniper would have to possess extraordinarily exceptional skills. That leads the detectives to one of Alvarez’s former recruits, Sergeant Aaron Barnes, who was particularly well-known for his marksmanship. However, when Barnes’ alibi doesn’t pan out, Gibbs discovers he actually was trying to cover up an affair, not a murder.
Then, another marine recruiter is killed in the same merciless manner in Bethesda, and now NCIS must fend off the FBI’s intervention since the murderer has crossed state lines. Still Gibbs, Kate and Tony (MICHAEL WEATHERLY) manage to elude the FBI’s watchful glare as they retrieve the bullet that killed this recruiter in his office, and Abby compares the two in her lab. At the scene, Gibbs also finds perhaps their most incisive clue: a white feather that he deduces is the killer’s calling card.
When Kate and Tony go back to the first crime scene, they find a white feather in that locale as well and decide that the same killer committed both murders. Gibbs ascertains that – if given the opportunity -- the murderer will go back and try to replicate his deadly success. Based on that notion, Gibbs decides to fill in as Alvarez’s replacement – baiting the killer with the announcement that the sniper’s cowardly act won’t shut down a recruiting office -- and Kate as his commanding officer on the scene. They have also determined that their culprit isn’t military, but a wannabe who has been turned down for service. With the FBI and Tony standing by the entire day, Gibbs waits for the sniper to make his move.
With Gibbs conducting the recruit interviews, Kate assesses each candidate who comes through to determine the killer. As the day winds down, no one fits the killer’s profile... until the very last would-be recruit. However, just as he leaves, a shot rings through the office’s double-plated window which – without that protection – would have struck Gibbs in the chest.
Thinking back, Gibbs and Kate realize that an innocuous water deliveryman is actually the killer as Abby triangulates on the shot’s origination – and Tony and the FBI agents seize on that location. Tony then must chase down the sniper... who pulls a gun on him, prompting the agent to shoot back and kill him.