After the attack on NCIS, the President orders all agencies to pursue Harper Dearing with "extreme prejudice". Meanwhile, Ducky tries to recover from his heart attack.

Abby has more nightmares; Navy Seabees continue to work on the building; a shrink does mandatory psychologic evaluations on all hands; the body of an armory worker appears four months after the explosion; Abby and the rest work out it all.

Ducky, on medical leave, unofficially calls for the exhumation of the body of a commander whose autopsy he conducted 12 years ago; he now suspects murder; the gang investigate another death, and they find the connection and the solution.

An inflatable raft washes ashore with three survivors from a missing Navy helo; the pilot also is missing; Gibbs and company plus Borin (of the CGCIS) investigate. The team and the other Abby find the pilot, the truth, and the chopper.

While the Gibbs team investigate a murder of a Navy petty officer first-class, Gibbs himself sees a Medal of Honor, which his father's former best friend received for valor during WW2. The gang figure out and work out both problems.

Two Marine officers return from Afghanistan after an ambush; one night one of them dies in a fistfight in an alley in Washington, DC; Gibbs and company investigate. The gang see a familiar face but do not yet find the person. [Continued.]

Gibbs tells Joe that Joe was right about Kersey's presence with the enemy in Afghanistan, and that he and the gang need his help to find the bad guy; Gibbs talks with Joe, his brother (Evan), and their father. Evan stays to help Joe, but their father goes back home in Ohio; Joe goes with Gibbs to see Paul, another member of the outfit, who responds negatively to Joe. Abby uses virtual-reality (VR) gear to help Joe recover some of his memories; the gang increase their efforts to find Kersey; Gibbs continues to work with Joe; they catch a clue; the gang find Kersey's car but not Kersey, then they find a girl with blue hair, then Kersey; then Joe suddenly recalls another face. Abby tells the site of the next incident, and McGee tells its significance; Gibbs and the team saddle up and head out; they find and seize first a package and then a ponytail. Joe reconciles with Paul; Tony gives Ziva an audio treat; Abby serves Thanksgiving dinner to the gang at Gibbs's pad.

A kidnapper shoots to death a Navy captain who intervenes; the bad guys get one teenage girl but not the other; both girls are Navy juniors; Gibbs and company investigate, pursue, solve, capture, and recover. Tony joins Ziva and her date.

A Navy seaman fires on Fornell, who returns fire and kills him; Gibbs and company investigate, along with Fornell and the mutual ex-wife of Gibbs and Fornell. The gang find frozen fish, a dead body, a missing accountant, and two bad guys.

A Navy Lieutenant Commander returns from an overseas tour to her home and finds the decomposing body of her husband. When Gibbs and his team investigate, they find a new kind of uncirculated $100 bills.

A human ear in the Potomac River leads to the rest of the body, wearing a uniform of a Navy petty officer; Gibbs and company investigate. Ziva's father shows up, as does his Iranian counterpart. Gunfire interrupts a dinner. [Continued.]

Gibbs and company continue to investigate the killings at Vance's home, seeking whoever hired the shooter; the gang identify the hit man and later figure out who's responsible. Ziva buries her father, and Vance and the team bury Jackie.

Two passersby find the bodies of a Marine and a young woman in a wrecked car; Gibbs and company investigate; Ducky raises questions. Flashbacks trouble Abby. The gang find anger, hostility, a feud, a history, a solution, and the bad guy.

Gibbs and company capture the world's number-2 cyberterrorist; as Ducky suggests, the gang use an unconventional technique to gain evidence from the stubborn bad guy; Tony and Ziva find the body of an Ebola victim; the team come out ahead.

A lance corporal collapses and dies on an obstacle course at the MCB, Quantico, Virginia; Gibbs and company investigate; Ducky sees many wounds. Another injured Marine dies. The team figure it out. Vance finds and solves personal business.

An injured Navy lieutenant commits suicide; Gibbs and company investigate; three people kidnap Ducky, Palmer, and the body, and the abductors demand an improvised autopsy. The gang find the missing body, teammates, answers, and bad actors.

Gibbs's barber confides in him about the former's son; Gibbs quietly asks around. Meanwhile the gang investigate the disappearance of $120K of Navy money; they suspect a Marine and his girlfriend. Gibbs and company work out both cases.

In Afghanistan a Marine sergeant, a dog handler, dies of a single round, said to have come from a Taliban sniper; his widow tells Gibbs about her doubt and the reason; Gibbs and company investigate and solve, then Gibbs arrests the shooter.

Aboard a destroyer of the US Navy during a storm at sea, the ship's medical officer dies, apparently by homicide; Gibbs and company investigate; McGee's father, an admiral, is aboard. The gang follow the tracks and catch the killer.

A Navy lieutenant returns home from TAD; her husband is missing, and the family room is a mess; Gibbs and company investigate; a suspect dies. The team assemble the pieces, and they bust two bad actors. Gibbs sends Ziva and Tony to Rome.

Orli, the new director of the Mossad, asks for NCIS assistance in hunting down a group of rogue operatives. Tony and Ziva travel to Berlin in their search for Ilan Bodnar.

Tony and Ziva, with only minor injuries, return to work; the others find the getaway car and the body of the wheelman, which provides a clue; Ilan contacts Ziva; Tony interprets the lead, then Ziva pursues it and draws the case to an end.

A Navy petty officer chases and attacks a man; he asks to speak with someone at NCIS; the gang solve. An official from the DoD starts snooping around, apparently on a witch hunt; he and a goon squad of grim feds confront Gibbs. [Continued.]

A familiar face defends Gibbs in Parson's investigation. While the team tries to help Gibbs, they must solve the murder of a Navy SEAL.