While working on his book with his graduate assistant Kasie, Ducky is watching an episode of American Pickers when he sees Mike Wolfe handling what Ducky recognizes as a possible murder weapon from a 16-year-old cold case.
Rejoining the NCIS team, Ducky assists them in looking into the matter. They retrieve the item, a ceremonial Viking war stick, and determine that it is indeed the missing murder weapon.
They track the war stick back to an antiques dealer in Falls Church, who they find dead in the alley behind his store. Curiously, he also had his head bashed in like the original murder victim.
The antiques dealer's last customer, Clarence Wyatt, denies any knowledge of what happened, but he paid a large amount of money for a World War II era pistol.
Eventually, the team realizes that Wyatt killed the original victim 16 years prior after the sailor had discovered Wyatt was stealing valuable antiques from a storage facility and selling them.
Wyatt later killed the antiques dealer to keep him silent about the Viking war stick/murder weapon.
Meanwhile, Kasie meets the NCIS team and immediately gets along with everyone, except for Abby. After an awkward confrontation, Kasie admits that she hero-worships Abby and was overcome on their first meeting.
Kasie discovers the DNA evidence to put away Wyatt for good.