NCIS is called to investigate the shooting of Lt. Mayne only to discover that he's been listed as M.I.A. and was last seen in Afghanistan six years ago. Mayne survives the shooting but is unable to speak preventing any of our agents from questioning him. When his wife, Leah Mayne, shows up at the hospital, where Mayne is in ICU, she's confronted by Rachel Wells who claims that she's married the same man who now goes by the name Christian Wells. Assuming a new identity, Mayne/Wells married Rachel and claimed to have inherited a lot of money from his family however Rachel knew nothing of his past. Mayne flatlines and dies before Gibbs is able to question him. We eventually learn that while Mayne/Wells was in Afghanistan he was part of a three person deep undercover mission to track down a drug lord and it went terribly array. Apparently Mayne, Lt. Holcomb and Sgt Gontz, concocted a plan to steal the money from the drug lord, and while Mayne stayed back and watched the money, the other two of them went in search for a vehicle. However, when they returned, Mayne was gone with the money. A few years later Holcomb hired a PI, Peter Iger, to track down someone whom he thought looked like Mayne. The PI lies and tells Holcomb that the man he saw wasn't Mayne. After realizing how much Mayne was worth Iger decided confront Mayne in an attempt to blackmail him for money in order to keep quiet about his past identity. The plan backfired and a shoot out ensued which eventually led to Mayne's death. Ducky's mysterious whereabouts and attire has everyone speculating about what he's been up to. We discover that not only did Ducky's ill mother pass, he already had a private funeral for her. His chipper mood is because he's become quite smitten with the realtor that selling his mother's house.