DEA Special Agent Mitchell asks the NCIS for assistance in bringing in a wayward Marine by the name of Cole Gleason, who has evidence which will help convict drug distributor he's been chasing by the name of Benson Long.
Mitchell believes Gleason has been hesitant about handing it over, as he has missed a meeting.
Mitchell tells the team that Long recruits military personnel to his group. Gleason is one of his latest recruits.
When the team is ready to go and arrest Gleason at Roy Evans house (Long's cousin), Gibbs tells Tony to hang back.
When Gibbs, McGee and Bishop arrive to attempt an arrest they discover that Gleason is gone. They confiscate Evans' gun.
Abby finds three sets of fingerprints off of the gun: Evans, Long and a third set of prints from Fisher Hyland, a drug trafficker.
McGee and Bishop question Hyland, who tells them Evans won the gun from him in a card game. He tells them Long asked him about a school rave as a possible location for drug deals.
They visit the school and discover the body of Cole Gleason. Ducky tells Gibbs that Gleason was dead before his scheduled meeting with Mitchell.
Tony tells Gibbs that he discovered that Mitchell's full name is Luis Mitchell, the son of Kurt Mitchell, the NIS agent who died protecting Gibbs' wife and daughter.
Tony and Bishop call on Hyland to go back to Evans' house and play cards with him and Long. Tony gives Hyland a card shuffler that has a wire in it.
Abby connects the fibers found on Gleason's body to a type of rug only sold in Evans' shop.
McGee, Gibbs and Mitch interview Evans at his store. Evans pulls a gun and McGee shoots him. Evans later dies in hospital.
They confiscate some rugs from Evans' shop, hoping to match their fibers with the ones found on Gleason's body. Though they are unsuccessful in making the match, Ducky and Abby discover drugs sewn into the linings of the rugs.
Tony, Bishop and McGee figure believe that Gibbs will do anything to protect Mitch. In looking through the old Hernandez file (in which it is outlined that Hernandez shot and killed Kurt Mitchell as he drove Gibbs' wife and daughter to a safe house; they died in the resulting crash), they realize Hernandez worked for Benson Long.
Tony confronts Gibbs and accuses him of waging revenge on Benson for the deaths of his family as well as Mitch's father. Gibbs assures him the case is above board, and that his intent is to prosecute not execute him. He tells him that Mitch is back at his hotel, and that they'll resume the investigation in the morning, but Tony informs him Mitch lied: he's at Long's house. Gibbs tells Tony he's going after him alone.
Tony disobeys Gibbs and he goes after him, taking McGee as well.
Gibbs confronts Mitch while he waits for Long at Evans' house. He talks Mitch down from wanting to shoot Long. Long claims to be untouchable as he brags about his crimes.
McGee rushes in and arrests Long based on that confession, captured by the card shuffler.
Gibbs travels to California to be with Mitch as he scatters his father's ashes into the ocean. He then travels to the house where he used to live.