Callen, Sam and Nell are sent to find a top-secret government device that was on a failed rocket launch. Deeks, Kensi and Eric interview a suspect from Proxima Systems, the missile manufacturer. Sam gets snapped at by the mission director. Hetty visits Harris Keane, who is having trouble re-acclimating after his years of being a prisoner in Vietnam. One search party is missing. Deeks and Kensi interrogate Chelsea Parker. Eric discovers that the coding was done by someone other than Chelsea. Her boss, Donald Jenkins, codes in that suspect way. Harris has been avoiding Hetty's calls. He's been writing letters to the families of people he killed. Sam and Callen find the search party shot dead. So someone else also is looking for the device. Franco Martinez, Jenkins' loan shark, offered to forgive his gambling debts if he caused the rocket to crash. Mosley wants to have Jenkins contact Martinez. Hetty and Harris visit the grave of George Nelson, who died from Agent Orange. Jenkins and Martinez go to meet Martinez's boss. A camping couple finds the payload and gives away its location over the compromised radio network, putting themselves in danger. Kensi is undercover at the meet as a bartender. The boss is Sajad Khadem, an Iranian intelligence official. He knows Jenkins had been arrested that morning and is threatening to kill him. One camper, Vanessa, ran to Callen and Sam with the device, but her boyfriend Dave refused to leave and is now a captive of Khadem's men. Kensi reveals herself and Khadem runs. She and Deeks shoot his men, then Deeks takes out Khadem with a golf club. Sam and Callen shoot the men holding Dave. Nell finds a bomb outside the search headquarters. Sam and Callen capture Gates, who was the mole, trying to escape with the device.