At an avionics firm in LA four armed thugs steal a flash drive containing software pertaining to a drone for the US Navy; Sam knows the lead engineer on the drone project; the G team figure out everything and find the bad guys and a child.

During a Marine-sponsored charity-benefit volleyball tournament at Venice Beach, a car bomb explodes, killing two and injuring 29; promptly an aggressive TV reporter, Dana, says on the air that, according to sources, an Iran-based Islamic militant group, the JLF, is responsible for the bomb. One honcho at the DoHS firmly denies that the JLF is responsible; G and Sam lean on Dana, who gives a name; Eric finds another lead; Eric and Nell exchange notes; Kensi and Deeks chat with a man who believes in alien creatures who watch everyone; G and Sam make a productive stop at a car-rental shop; Kensi and Deeks learn some disturbing news; Dana dies, and Sam collars her killer, Bakri Deng, from South Sudan, who first refuses to cooperate; Kensi and Deeks learn about Deng, and Eric and Nell learn even more; G and Sam find the truth and an explanation, then, with Deng's help, they intervene with two other bombs and bombers and neutralize them. The foursome also receive love notes.

The team goes beyond boundaries to make sure Hetty is safe but what they don't know is that Hetty has her own plan as always. Meanwhile Nell is having a hard time after having killed for the first time and is visited by a know face who might be able to help her.

When a man is murdered by a small drone, the team discovers his connection to a terrorist group that is planning another local attack. With time running short, Nell must use her drone expertise to try to divert a disaster in Long Beach.

Sam reflects on his own upbringing and relationship with his father when the team investigates the murders of marines who have sons in military academies.

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.

Calllen's routine operation becomes anything but. Posing as a mailroom clerk in order to get close to a suspected arms dealer, he becomes a hostage when terrorists take over the office.

The team searches for those responsible when a missile test is hijacked; a young computer specialist assists the team.

Kensi faces hard memories from her past.

Callen and Sam receive a cell phone on their day off and the caller threatens to kill innocent people if they don't do as he says.

The team investigates the murder of a tech entrepreneur turned venture capitalist who secretly developed a computer program that allows for undetectable data collection.

The team searches for a North Korean spy while they're assigned to protective detail for the commander of the Pacific Command.

Sam insists Callen find a new partner while a threat of a North Korean attack looms.

The team is in danger when their pictures are included on a cartel hit list.