A woman spots a disemboweled man on a fire escape. Gibbs checks in with Fornell, who is working undercover at a Beltway Burgers. The dead drug pusher Fornell found had worked there. The team is hung over after Gibbs had joined them at the bar for McGee's celebration. The body belongs to Navy recruiter Diego Barnes. McGee recovers the knife used as the murder weapon. Palmer finds the corner of a larger piece of paper inside Barnes. That paper had been a treasure map. Barnes, a treasure hunter, was pursuing the Demint Treasure. Fornell discovers a locked box in the freezer, which opens with the key he took off the dead pusher. The box is full of drugs. Gibbs and Bishop meet Demint's daughter Margot, then Angus himself. Angus won't give up the location of his treasure, to help the investigation. Margot brings in documents to NCIS that she took from her father's computer. Barnes got into a fight with two other climbers the night he died. Torres and McGee interrogate them. Angus talked to Barnes the night he was killed. Angus's house is trashed. It was staged and Angus is hunting for the killer. Fornell calls with the name of the drug kingpin, Meriweather. Gibbs calls Margot for help. Kasie and Bishop figure out where the treasure is buried. Angus and Camille get arrested. Simon, the climbing-gym worker, abducts Margot to force Angus to reveal where the treasure is buried. Gibbs has Angus send him to Gibbs' cabin. Gibbs had written "Duck" in Morse code. Margot understands and does so and Simon gets shot. Angus and Margot dug up the treasure and used it to start a foundation in her mother's name. Fornell has been missing for two days when Gibbs next goes to Beltway Burgers.