At 02:15 one morning a Navy lieutenant (j.g.), Brian, with two gunshot wounds, in a car not his own, drives into a canyon from Mulholland Drive in Los Angeles, then dies; Callen and company, including Deeks, investigate; Deeks has a couple of awkward moments; the team pick up several clues about the circumstances of the preceding night, including Aubrey, a young socialite woman. Kensi and Deeks speak with Aubrey's stepfather. G, Kensi, and Deeks go nightclubbing; Kensi discovers an alive missing girl, and she says that a victim just became a suspect; the team meet several interesting people; Kensi decks one and cuffs him, and G pops another one; the team escort away Aubrey, who gives Kensi much useful information. Kensi and Aubrey go to the latter's home, where Kensi sees more clues, more people, and a part of a solution; Aubrey leaves, Kensi gets into trouble, and G, Sam, and Deeks ride to the rescue. The team finish putting together the pieces about the death and more.

In a parking garage on Rodeo Drive in Beverly Hills, California, near Los Angeles, two shoppers find the body of a man less a crudely severed hand, which is missing; the victim was a Marine corporal, stationed at Camp Pendleton and assigned as a clerk in the G2 (intelligence) office with a top-secret clearance; Vance has expressed interest, so Callen and company investigate. Nell, an enthusiastic new analyst who finishes the sentences of others, has arrived for duty. Eric and Nell see a clue about the amputation; the musketeers conduct interviews; Eric and Nell find more clues; G and Sam find a body and another severed hand; Kensi, Eric, and Nell follow a trace to a Muslim jeweler in Beverly Hills; G and Sam start toward a lunch but bump into the jeweler and some friends; Kensi and Deeks meet the jeweler's wife and find a bloody knife; Sam adds a factoid; the team seek and find the real killer and the rest of the story. Kensi arranges to make a special delivery.

An unidentified man dies after a beating and a burning; a specific radiopharmaceutical in the body implies a connection to a previous case; Callen and company grab the bad guy. Hetty resigns, disappears, and reappears in Prague. [Continued.]

While raiding a pawnshop, targeting a Mexican drug cartel, LAPD cops kill two cartel grunts plus a wanted Muslim terrorist; the LAPD requests help from Callen and company, who seek, find, and scrub an alliance between the two rogue groups.

G and Sam acknowledge the fifth anniversary of their service as partners. Just outside the LAX airport four masked armed men stop a bulletproof van of the Diplomatic Security Service of the US Department of State, moving two couriers and a wooden crate, having originated in India and now bound for a warehouse in downtown Los Angeles; the bad guys seize the crate and escape with it; Callen and company investigate. G and Sam interview the couriers; Eric and Nell trace one of the trucks, two of the bad guys, and a van; then Kensi and Deeks find the van and the crate, check out the contents, and take part in a gunfight; a crew takes possession of the crate. Granger, the new assistant director, shows up and shows interest; Kensi and Deeks find a body and shoot a fed to death; G and Sam meet a private aircraft and suddenly meet also more people than expected; Sam attacks G, but Kensi and Deeks ride to the rescue; back at the boathouse the team put it all together.

The LAPD releases G after an overnight stay in jail; Sam meets him; the two exchange words; G leaves in a taxicab with a tail. At the boatshed Kensi and Deeks talk with Atley, who describes certain matters, including an insurance policy nearby; while Sam watches, an Iranian briefly chats up G, who soon walks away; another Iranian approaches Hetty, but she brushes him off; later G sees the two Iranians together, and he makes a deal with them; the CIA demands an immediate arrest of G; Granger asks Nell for a warrant for both murder and treason; Deeks picks up an item from a bank, company pursues, and fireworks ensue; Deeks drops a briefcase, and an Iranian picks it up; Eric snoops and produces; the Iranians beat and question G; Sam, Kensi, and Deeks make a road trip and take a passenger; the team make another swap; Sam hands G's badge and piece back to him; Hetty returns to her office, and Granger returns her resignation; the two of them chat about their "audacious plan".

A thief steals a used notebook computer from a store; a car hits the thief, and two occupants of the car stuff the victim into the back seat; the thief is Amir, the nephew of Yusef, whom Sam still owes on a debt incurred in Afghanistan some years ago; a third occupant of the car, Habib, is a known terrorist; Callen and company investigate (after several tense moments at the start). While Sam visits Yusef, bad guys drive by and open fire; Sam returns fire and drops one of them, Ali, a member of a radical jihadist group; Eric learns that Ali and Amir knew each other; Kensi and Deeks meet Nicole, Amir's girlfriend; Sam follows Ali's brother, then he and G find an arsenal; Kensi and Deeks go back to Nicole's pad, where they find her in trouble, and where they exchange fire with bad guys, rescue Nicole, and see a photograph; Deeks experiences enlightenment; Sam goes back to the boathouse, where he enters a mess; G, Kensi, and Deeks pitch in, then everything works out.

Monica becomes the target of an unknown shooter in Hollywood; Deeks, in an undercover role as Max (at the direction of Granger), rescues her; Monica is a hostess at a nightclub, which is a property of a South African who's now a legitimate businessman, but who previously worked as an international dealer in illegal arms. G and Sam visit the club, and Nell identifies the shooter as Pieter, an enforcer from South Africa; G and Sam take a different tack with Pieter, so they meet him and take him to the boathouse; Max has an unusual short-term relationship with Monica, who steals blood diamonds and shows them to Max, then both she and the stones disappear, but Kensi and Deeks find her and them. G and Sam chat with Pieter, who reluctantly talks; Kensi and Deeks chat with Monica, who agrees to cooperate; the team monitor an exchange, minimize the damage, and grab three bad guys; later Kensi and Deeks get something clear. Granger never shows up.

The team investigates a burglary at a cyber-security company, but Callen must steer clear of the crime scene after Hetty reveals his girlfriend, Joelle, is one of the lead witnesses. Also, the team discusses their personal holiday travel plans. Kensi and Deeks are given the chance to get even closer to each other.

Callen and Sam are sent covertly to the U.S. Consulate compound in SFAX, Tunisia to collect and retrieve key evidence after an assassination attempt on an U.S. Ambassador.

Kensi faces hard memories from her past.

The team and the FBI team up while investigating a soldier's death.

The team works with the Global Criminal Tribunal when a Syrian seeking justice is brutally attacked while delivering evidence that would prove chemical weapons were used on civilians.

The team investigates the murder of a journalist who was writing an exposé on a mishandled classified military operation. Also, as their wedding day quickly approaches, Kensi and Deeks work on the last remaining items on their to-do list.

CIA Officer Veronica Stephens (Dina Meyer) asks the NCIS team for help when an agricultural engineer Hetty asked her to bring to the United States disappears.

"Commitment Issues" - The NCIS team investigates the murder of a Naval warfare engineer at a spoken poetry event. Also, Callen asks Nell to assist him in a worldwide search for Anna's whereabouts.

When a Russian bomber goes missing while flying over U. S. soil, Callen and Sam must track it down in the desert and secure its weapons and intel before the Russians on board destroy the plane. Also, Hetty gives Nell a cryptic assignment.

When military grade technology is stolen, a deaf engineer, Sienna Marchione, who always wanted to serve her country, and the only member of her team to survive the theft, helps Kensi and NCIS track down the tech before it's taken out of the country.

As Callen continues hunting Katya, Kilbride enlists NCIS help to find a truckload of stolen guns; the assignment becomes more challenging when their suspect is found dead.

NCIS investigates the murder of a woman employed in the Navy's missile defense program and its connection to stolen Navy missile technology. Also, a strict social worker stresses out Deeks, and Sam debates selling his boat.