NCIS is called to investigate the shooting death of retired Master Sergeant George Hawkins.
Hawkins is found with the dog tag of his deceased friend Charles J. Kent - with whom he'd served in Vietnam. Abby later learns that the dog tag is fake, and Hawkins knew it - which leads Gibbs to believe that his final act as he lay dying was to reach out to the tag, in order to give those who investigate his death an important clue.
Bishop learns that Kent had died in Hawkins' arms, after an ambush by the Viet Cong back in 1969. Ever since, Hawkins had done everything he could to bring back his friend's remains for burial.
Abby uncovers evidence that the fake dog take had been delivered to Hawkins in an envelope unique to a travel agency called "Blue Summit Travel".
When Tony and McGee visit the agency, McGee notices that the writing of one of the ex-employees - Henry Caldwell - matches the writing on the envelope that contained the fake dog tag.
Gibbs and Bishop attempt to apprehend Caldwell. Gibbs orders Bishop to go around the back of the building, but when she hears a loud crash in the kitchen, she pursues him there instead. Caldwell escapes through the back.
Bishop notices that one of the pictures taken by Hawkins in Vietnam contains the image of a little boy who was wearing a medallion with some lotus blossoms on it. This was a boy named Ky Van Tu, whose parents had died, after which Kent and Hawkins helped him to bury them.
McGee and Tony capture Caldwell at a pharmacy and bring him in for questioning.
Caldwell tells Gibbs that he had been running a scam, in which he had received information from a charity about missing armed forces personnel. He had used that information to target people who were searching for their loved ones. He would create fake dog tags as proof that he could find them, and then ask for more money to search further. Caldwell told Gibbs that his partner in the scheme was Todd Price - the owner of Blue Summit Travel.
After Abby determines that a gun found in Price's home was the one used to kill Hawkins, the team discovers that he has fled to Da Nong, Vietnam.
Tony and Gibbs pursue him there and arrest him at his girlfriend's place.
After Bishop discovers that one of the artifacts recovered at a site matches the medallion she saw in the picture of the boy posing with Kent in one of the old photos Hawkins had taken, the team is able to locate the now grown man - the little boy in the picture. They learn from him that he had taken Kent's body after his death, so that he could bury him in honor next to his parents. NCIS is able to recover the boy and real dog tags, in order to return them home to his family.
Meanwhile, Bishop confronts Gibbs about his being so easy on her. Gibbs admits he had done so over guilt about losing the two people who occupied Bishop's desk before her, and that he figured it was because of something he had done wrong. So he had treated Bishop differently, not wanting to make the same mistake again.
Bishop asked him to push her, so that she could be an outstanding agent like Tony, McGee and Gibbs. Gibbs agrees, then tells her to stop sitting on the floor and to sit at her desk.