NCIS feverishly investigates a global terrorist group that is recruiting teens via the Internet following a deadly bombing overseas that results in an emotional and surprising loss for the team.

The NCIS cyber case turns into a united global effort after evidence confirms "The Calling," an international terrorist group that recruits children through the internet, has been purchasing S-bombs off the black market.

Special Agent Ned Dorneget from NCIS cyber operations assists the team when a Navy ensign who worked in the Office of Naval Intelligence is murdered. Also, the team discovers that Jake and Gibbs have become good friends.

Gibbs and Bishop travel to Afghanistan after the murder of a Marine in D.C. is linked to a terror group holding another Marine hostage overseas. Also, DiNozzo is upset that McGee was chosen to be the new face of NCIS for all recruitment brochures.

DiNozzo is partnered with his girlfriend ATF Special Agent Zoé Keates after evidence reveals that the murder weapon in an NCIS case was originally purchased for the controversial ATF sting operation "Operation Fast and Furious." Also, Anthony DiNozzo Sr. returns to town for a special dinner to meet his son's girlfriend.

The murder of a petty officer sparks a lead in a 40 year old airport bombing cold case that Gibbs and DiNozzo have been assigned to for the past two years. Also, McGee is jealous that he was not previously briefed on the cold case.

After the body of a thief is found in a Marine's house, NCIS discovers the calling card of a terror group Delilah and the Department of Defense have been tracking.

Evidence in an NCIS murder case reveals a rare painting on loan had been swapped for a fake, prompting DiNozzo, Sr. to share his knowledge and contacts of the black market art world with the team.

Covert identity created for one of Gibbs' undercover cases 20 years ago resurfaces after a murder victim is found living under the alias.

The NCIS team suspects Gibbs' arch-nemesis is behind an explosion at a summit for global terror event, but Gibbs elects to sit out the investigation in order to help a grief-stricken Fornell, whose life is on the verge of imploding following his wife's murder.

DiNozzo returns to the military academy he attended as a teenager after a murdered Marine and alumni of the school is found clutching the photo of a current student. Also, Bishop and her husband invite Gibbs and the team out for a special dinner.

Gibbs and the team investigate when a Navy lieutenant who is set to be the first openly gay servicemember to receive the Medal of Honor is murdered. Also, as his wife's due date approaches, Palmer prepares for fatherhood with a NCIS baby shower.

The NCIS team searches for a home-grown terrorist after a rescue mission in Syria reveals an American was involved in the capture of a social worker. Meanwhile, McGee and Bishop question DiNozzo's unusual behavior.

The NCIS team must investigate a series of crime scenes that appear to be copy-cats of previous cases. Also, two of Gibbs' ex-wives, one of which the team has yet to meet, show up at a crime scene to discuss something important with him.

The NCIS team consults with three cyber-terrorists they imprisoned after a city-wide Internet shutdown the week before Christmas. Also, McGee reflects on the case and Gibbs' infamous rules as he pens a heartfelt letter to his father.

While stuck at the Dulles airport due to inclement weather, DiNozzo, Bishop and her husband Jake work an NCIS case involving an elevated terrorist threat at Northeast airports during the Thanksgiving travel surge.

While the NCIS team investigates the cause of a hit and run accident that resulted in the death of a Petty Officer, Gibbs searches for a way to clear a Navy Hospital Corpsman, who has served two medical tours in Afghanistan, after she's indicted for illegally providing medical aid to the victims of the crash, even though the surviving victims swear by her life-saving techniques.

After investigating the murder of a retired Master Sergeant, the NCIS team uncovers a fraudulent charity that preys on those searching for missing military personnel. Meanwhile, Bishop agonizes over the results of her probation evaluation, and Tony contemplates adopting a stray cat that followed him home.

The NCIS team must determine if the murder of a Navy commander's wife is linked to her profession as a therapist or an act of terrorism after finding the commander's name on a Jihadist target list. Meanwhile, the team discusses Halloween costumes and Tony's recent dating habits.

During a joint Coast Guard and NCIS training exercise at sea, Gibbs and CGIS Agent Borin spot a deceased man overboard, who is discovered to be a missing crew member from a ship 60 nautical miles away. Upon boarding the ship for questioning, Gibbs finds himself on a vessel that has been commandeered by pirates.

The Secretary of the Navy assigns the NCIS team to a joint terrorism task force after a Naval research scientist is murdered and the lead suspect is wanted by the Russian government. In order to get a jump on the case, Gibbs has DiNozzo run interference with the leader of the task force, FBI Agent Leia Pendergast.

When an NCIS case reveals a connection to Ducky's estranged childhood best friend, he and Special Agent Bishop travel to London for interviews with family and co-workers of his friend. While there, Ducky finds himself reminiscing about the choices he made in his past and the subsequent impact they had on his adult life.

When a Navy Lieutenant is killed on his way to a private meeting with the President, the NCIS team must determine if the murder was part of a recent stream of muggings in the area or a targeted hit to keep intel secret.

Gibbs and McGee travel to Russia to safely escort home an NCIS computer engineer connected to classified intel, but their mission is compromised and they are forced to go off the grid while hunted by a Russian mercenary group. Meanwhile, the team in D.C. frantically uses every asset and inter-agency contact they have in an attempt to locate their missing team members