During a training exercise for a top-secret mission, a fifth generation Navy officer and SEAL, Lieutenant Rick Johnson, rappels down a cliff when his carabiner – a D-Link – snaps, and he gruesomely falls to a death. Hours after the incident, Gibbs (MARK HARMON), Tony (MICHAEL WEATHERLY), Kate (SASHA ALEXANDER) and Ducky (DAVID McCALLUM) arrive at the scene, greeted by Commander Michael Rainier, who seems to vehemently insist that the horrible accident is just that. Initially, the agents interview Johnson’s men who had gone down before him in the exercise, and recover the victim’s D-Link. Handing that off to Abby (PAULEY PERRETTE) for further investigation, she discovers that the link is different from the manufacturer’s: theirs is steel while his has been re-fashioned with aluminum. Back at NCIS, the agents now move their suspicions about Johnson’s death from accident to murder.
When the agents re-visit Rainier, he continues to be reticent about helping in the investigation until Gibbs tells him that they now believe that Johnson was murdered. Rainier -- who heretofore had insisted the current mission is classified -- relents by cooperating with the agents. He also relays that, now more than ever, finding Johnson’s killer is urgent: in less than 48 hours his unit is still to head off on a mission that could affect national security. Therefore, Rainier must find out if someone is jeopardizing that operation.
While Abby also checks the identity of fingerprints on the D-Link, the agents next visit Johnson’s wife Denise to determine any possible clues at his residence. Kate notices that Johnson had been sleeping on a sofa, and at his home, they also meet his priest, Father Larry Clannon. Nothing seems out of the ordinary until Abby identifies the D- Link fingerprint matches Denise Johnson. She has a criminal past as a car thief, and now works at a jewelry store – with metals such as aluminum – meaning she could have tampered with the D-Link. But Denise’s answers to the agents’ questions make her less suspect, and she gives them his computer for further investigation. The agents also find that one of Johnson’s men, P.O. Second
Class Vengal, had been written up several times by the lieutenant, making him a possible suspect. But suspicions about him also wane when they realize Vengal’s dedication to the mission is such that he would never do anything to endanger it.
Uncovering Johnson’s cell phone, the agents find that he placed two of his last calls to his priest. And, with nothing but dead ends, the agents decide to re-stage the accident, while Abby works with Agent McGee to uncover any clues via Johnson’s laptop. As they discover that Johnson had a secret e-mail address, the agents’ re-creation of the cliff falls prompts Kate to pose the question of how an experienced climber like Johnson couldn’t know – as he was preparing to rappel -- that his aluminum D-Link weighed lighter than a steel one would.
The agents visit Denise again with these latest revelations, and she discloses a part of Johnson she was trying to save anyone from knowing. She had actually just discovered that Johnson was using his private e-mail to rendezvous with another man who he was having an affair with. Believing that he might be seeing another woman, Denise had followed him on one occasion and was shocked at her discovery. She could never bear to bring it up with him. Since Johnson was a fifth-generation Navy man, she knew how important the “Don’t Ask, Don’t Tell” direction was. The agents also learn that Priest Clannon blames himself; Rick was very religious and Larry had been trying to help him cope with his inner conflict. With Johnson’s death now ruled a suicide, Gibbs gives the go-ahead for the SEAL mission to continue.