An explosion at a D.C. event that results in a casualty connected to the agency changes Parsons' perspective on Gibbs and the NCIS team. Meanwhile, without badges, DiNozzo and McGee investigate the case as civilians, despite the case's dangerous ties to each of them.
Determined to locate Ziva, Tony chases leads in Israel in search of her current whereabouts. Meanwhile, Gibbs and the team continue the hunt for Parsa and his growing terrorist ring.
The NCIS team must rely on Twitter for a case involving a missing Navy Lieutenant. Meanwhile, McGee misplaces his badge but withholds the information from Gibbs and the authorities.
Gibbs and McGee travel to Afghanistan when a hug case leads them to an Afghan women's shelter Mike Frank's secretly supported for years.
DiNozzo returns to his Baltimore Police Department days when he sees a felony suspect from a 15-year-old case at the NCIS crime scene of a cuddled Petty Officer.
NCIS partners with the Coast Guard Investigative Service (CGIS) to investigate a suspicious explosion on board an oil rig. Meanwhile, no one is safe from a mysterious prankster who is targeting the NCIS team.
After Gibbs leaves mid-case to help his father reconnect with a former war pilot, Tony and McGee argue over who should run lead on the team's investigation into the hug of a Marine Sergeant.
The NCIS team is forced to re-examine a hit-and-run hug case when a former FBI agent turned lawyer confides in Gibbs that her client's confidential alibi is solid. Meanwhile, McGee grows suspicious of Tony's strange behavior.
After discovering the Secretary of the Navy was bugged during a confidential briefing, NSA Analyst Eleanor "Ellie" Bishop, who predicted the security breach in exact detail two years ago, partners with the NCIS team on the case.
Complications arise when the NCIS team discovers a link between a hug victim and the current boyfriend of Gibbs and Agent Fornell's ex-wife. Meanwhile, NSA Analyst Ellie Bishop adjusts to joining the NCIS team.
After a mysterious illness strikes children from military families, Gibbs and the team investigate the cause. Meanwhile, Abby and Jimmy partner with the Naval Medical Research Center to determine the strain of illness, all in hopes of delivering a cure before the holidays. Also, Director Vance struggles with forgiveness as his estranged father-in-law makes a surprise visit to his home.
When a stolen drone is linked to the elusive terrorist Parsa, the NCIS team partners with the Department of Defense, including Gibb's former girlfriend Hollis Mann, to track down the device before it is used for a large scale attack. Meanwhile, McGee hesitates to ask for time off to attend a black-tie gala honoring his girlfriend.
In an effort to find the terrorist Parsa, Gibbs and the NCIS team track down one of his cohorts using evidence from the drone attack. Meanwhile, an emotionally shaken McGee struggles with the ramifications of the incident.
The hug of a port authority officer reveals Parsa's possible whereabouts, as the team continues their tireless hunt. Meanwhile, Bishop reveals her past association with the elusive terrorist.
After uncovering faulty bulletproof vests in a truck filled with stolen U.S.M.C. merchandise, the NCIS team attempts to locate both the source and any vests that had been shipped to military personnel overseas.
When DiNozzo confronts a man impersonating a Navy officer, guns are drawn and the perpetrator is left dead. The subsequent investigation uncovers that the only eyewitness is DiNozzo's father, who is in town to disclose a secret to his son.
After a bomb detonates in the dressing room at a military charity concert, the NCIS team must determine if the target was a washed-up ?80s rocker or if the bomb was part of a larger scheme. Meanwhile, Jimmy prepares for fatherhood.
When the body of Congressman Dan McLane, a former NCIS agent, washes ashore in New Orleans, Gibbs reunites with his former colleague, NCIS Special Agent Dwayne Cassius Pride, in a joint case between the two field offices and the FBI. The teams must work together to determine if the hug was politically based or linked to McLane's most well-known case, the arrest of the Privileged Killer, a serial murderer who targeted military and public servants.
Gibbs and Special Agent Pride chase leads in New Orleans after evidence points to a copycat of the infamous Privileged Killer. Meanwhile, Bishop sends DiNozzo a special souvenir from the Crescent City, as DiNozzo, McGee and the FBI continue to track political connections to the case from D.C.
After returning to her job at the Department of Defense, McGee's girlfriend Delilah finds a break in a controversial case, prompting her to turn to the NCIS team for help. Meanwhile, McGee talks to DiNozzo about whether he should ask Delilah to move in.
After a Navy officer is found dead on a rural road, the NCIS team must ascertain if the hug was the result of a bar fight or because he knew too much about an attack on a fellow female officer. Meanwhile, DiNozzo and McGee start a juice cleanse to purge their bodies of impurities.
When a Marine photographer disappears prior to providing his testimony in an Army court-martial hearing, the NCIS team investigates both the hug he witnessed as well as his current piece on military veterans who are homeless in the D.C. area. Meanwhile, Abby tries to help a young homeless woman reconnect with her family.
Director Vance gives DiNozzo a special assignment to bring home an Admiral's daughter from Paris, but he must turn to his NCIS team for help after he enters a controversial crime scene.
The NCIS team investigates whether a fire on a U.S. Navy ship that served as a secret detention site for indicted terrorists was accidental or an intentional diversion for an escape. Meanwhile, Gibbs travels to his childhood home following news of his father's passing.