Dr. Taft and Gibbs are playing chess at Gibbs' house and Taft is trying to get Gibbs to open up about his childhood. But Gibbs isn't having any, and he turns down Taft's offer for Gibbs to see Taft's therapist Grace Confalone. Gibbs says, "I said I would talk, but no shrinking."
They get interrupted when their phones ring. Gibbs is called to the scene of a murder; Taft to the hospital to do surgery on a gunshot victim.
Navy Petty Officers First Class Janet Shor and Lamar Finn were on patrol when they came up on a robbery. Finn was shot and killed and Shor is wounded. What was stolen were several crates of M16 rifles and a few thousand rounds of ammo.
Gibbs calls Taft and tells him to keep the robbery suspect alive until he gets there. But he dies on the table.
The dead man is identified as Fritz Beimler, who is a wanted man in Germany. Taft comes to see Ducky because Beimler has a weird scar and Taft wants to see it again. When they open it, they discover a metal plate that was originally implanted in a Catholic priest in 1995 to repair his busted leg. But Father Carlin left the States in 1998 to do missionary work. His family lost contact with him in '03. He's presumed dead in the Sudan, where Beimler was before he came to the U.S.
Because of the Sudan connection, DiNozzo and Taft, who has insinuated himself into the case, go to see Jeanne and her husband David Woods because they might know something that can help the case. David explains it is not uncommon to rob graves for parts in the Sudan. He will make some calls.
Taft lets it slip that the case is also about stolen guns, and Jeanne gets angry because she thinks it is about her father and DiNozzo lied to her.
McGee and Bishop go to see Shor. There is an ATF Special Agent there named Earl Kitt. He asks them to keep him in the loop. Shore says she can describe the main man, so Bishop pulls out an identikit.
Taft tells Gibbs he is enjoying the thrill of the chase while they are at the diner. A woman comes up. Gibbs thinks that it is Taft's shrink, but it is Taft's wife Catherine. She thanks Gibbs for being Taft's friend. She thinks the sparring they do is good for him. Gibbs says not as good as it is for him.
Bishop calls Gibbs. Metro PD found the van. There is no sign of the M16s but they found blood on the front seat.
Meanwhile, Ducky found another bullet in Beimler buried in some scar tissue, which Abby traces back to Jeanne's father Rene, aka La Grenouille. DiNozzo is upset because he promised Jeanne the case had nothing to do with her father. But it is unavoidable when the fingerprints on the steering wheel are a match for La Grenouille's henchman, Oskar Bruening.
Gibbs takes Jeanne into the conference room. He tells her they just found out about the connection to her father, but he and she aren't suspects. What he needs from her is anything she knows about Bruening. Jeanne recalls that he was her father's driver, but he had a different name -- Pierre.
David tells DiNozzo he knows all about his affair with Jeanne and when affairs end badly, which theirs most certainly did, they always stay under your skin whether you want them to or not. David says he isn't giving Jeanne up. DiNozzo reassures David.
McGee finds a Pierre Oskar in the database. Taft wants to tag along, but Gibbs says no. Go spend time with your wife. When the NCIS team gets to Oskar's house, he is dead. The ATF comes in just as Bishop finds detonators.
Taft and Catherine are coming out of a movie. Taft gets a call and Catherine goes to start the car. It doesn't start. It is making a sound she never heard before, so she goes to tell Taft and it explodes.
Gibbs comes to see Taft and Catherine at the hospital. Taft thinks the bomb was revenge for letting Beimler die on the table. Taft says who is he to be playing a cop? Taft says he and Catherine are going to take a trip.
When Gibbs gets back to NCIS, Bishop tells him that ATF called and said they found the guns but too late. They are on a plane to the Ukraine to be sold on the black market.
Gibbs drags Earl Kitt in for an interrogation. Kitt finally admits there is a top secret op. They installed tracking chips in the guns. It seemed like a good opportunity to test the system. Rather than scooping the guns up, they want to see where they go. Gibbs says these men killed a petty officer and almost killed his friend. Kitts says it's a tough call, but he admits the guns are still in the U.S. and they are tracking them.
The NCIS team gets the third gun runner.
DiNozzo goes to see Jeanne to tell her the guns have been found and they got the guy. He also tells her if he had one wish, he would turn back the clock to right when they got back from South Sudan because that was a much better ending for both of them. Jeanne said she would go back further. They say goodbye.
Gibbs is at the diner. A woman talks to him about her crossword puzzle. Taft comes in and sees them together and leaves. Gibbs sees Taft leave and realizes the woman is Grace. She says, "That is Dr. Confalone to you. Are you ready?" To which he responds, "Yes."