Two park rangers find the burned body of a Navy test pilot on leave in a forest in the Appalachian Mountains; Gibbs and company investigate; McGee sees evidence that the pilot tried to fly a jetpack. The gang figure out what truly happened.
A Saudi Arabian limo driver dies in an explosion of a car aboard NAS Patuxent River; Gibbs and company investigate; the apparent target is a Saudi prince present there for advanced training. The gang figure it out. Tony's father visits.
Tony and Ziva escort a whistle-blower from Paris to Washington, DC; during the flight they meet a federal air marshal, and they all encounter various problems. Gibbs, McGee, Ducky, and Abby help in Washington, and everything works out.
A Marine lance corporal's car explodes; while Gibbs and company investigate, McGee finds radioactivity. Ducky says that the dead driver is not the owner. The people around DC panic about dirty bombs. The gang figure it out and wind it up.
The death of a Marine veteran gets the attention of Gibbs, Fornell, and the gang. Damon reappears, then he and Ziva pose as truckers. McGee and others figure out everything, then Gibbs, Fornell, Damon, and Ziva round up the bad guys.
A Navy captain dies of gunfire while with his fiancée, who is Gibbs's first mother-in-law. While Gibbs and company investigate, they find several discrepancies and inconsistencies. Gibbs figures it out, and he and "MAllison" work it out.
A shooting takes place in Rock Creek Park in Washington; the victim is a Marine officer who became MiA six years before; Gibbs and company investigate. A second life, name, and wife all come to light. The gang solve it and nab the shooter.
While investigating the deaths of a diver and a captain, Gibbs and company meet two special agents of the Coast Guard Investigative Service, who present similarities to the gang. They all cooperate, find the truth, and nab the bad guys.
In Norfolk a Navy lieutenant and base-newspaper reporter dies of stab wounds to the back, as have three other men, and as does one more; Gibbs and company investigate, with the help of a former madam in Washington; Gibbs finds the killer.
The body of a Navy petty officer, shot and drowned, washes up on a beach; while Gibbs and company investigate, another body, wrapped in chain, turns up. The FBI becomes involved, the gang find clues, and Fornell and Gibbs find a leak.
A Navy lieutenant, otherwise in perfect health, dies under mysterious circumstances; Gibbs and company investigate; the vic's sister disappears; a long-time friend of the siblings recently died. The gang figure it out and bust the killer.
The body of a Marine corporal, minus his feet, shows up in the trunk of a junked car; Gibbs and company investigate. Abby and McGee go to Mexico on business; Abby returns with concerns. The gang figure out who killed the Marine and others.
The body of an NCIS agent turns up in a bonfire on a beach near the US Naval Academy after celebrations just before graduation; Gibbs and company learn also about a rape of a sailor, and Gibbs goes to see Franks in Mexico. [Continued.]
Gibbs meets Paloma, the head of the Reynosa drug cartel in Mexico; he gets a ride to Washington, where he talks with Vance in code. Tony and Ziva arrest a bad guy, who then dies. Ziva attends a ceremony. Paloma meets Jackson. [Continued.]
Paloma's goons shoot up Jackson's store, but he escapes, then he stays with Jethro. A helo lands, and two die, as do an agent and another person. Rivera takes matters into his own hands, but he produces an unintended and unexpected result.
At the high school at Quantico, students and teachers fall asleep while in class; Gibbs and company investigate; one girl disappears. A grandfather both helps and interferes. Temp interns join. The gang solve the case and find the girl.
A woman Marine sergeant, who's a bomb-disposal tech, shoots to death an intruder in her pad; Gibbs and company investigate; Fornell and another FBI member become involved. The gang find everyone and figure out everything; it all works out.
The body of a petty officer shows up in a hot tub; Gibbs and company investigate; Ducky sees an unusual clue; Abby finds a link to the Royal Navy. A Royal Marine major and a CIA agent prove to be something else. The gang catch the bad guy.
A shooter kills three people, including a Navy commander, on live talk radio; Gibbs and company investigate; they believe that the host was the main target. The gang pursue clues to a bomb at a baseball diamond, where they nab the bad guy.
A Naval Reserve lieutenant, who's a chemical engineer, dies when a city bus accidentally hits her on a street in Washington, DC; Gibbs and company investigate. Abby deciphers mysterious writings; the gang figures it out and nab the perp.
An admiral finds the body of a long-time friend; Gibbs and company investigate. Tony and Ziva pick up Tony's father, who appears to have become connected with the victim. Sr. does a favor, and Ziva accompanies him. The gang figure it out.
Vance hosts a conference of high-level members of the NCIS; he invites Eli, who accepts. Eli's presence raises security concerns; Gibbs and company take part in the protective arrangements. Threats arise, and the gang respond. [Continued.]
An attack has killed one and left Vance with serious injuries; Gibbs takes charge by Vance's order. Eli reveals details about an operation 22 years old. Gibbs and the gang put the pieces together. The bad guy emerges, and justice prevails.
A Navy petty officer, who's the only witness in a civilian capital-murder trial, disappears; Gibbs and company investigate in response to a request by a commonwealth attorney. The gang puts all the pieces together, and justice prevails.