When the murder of Pedro Hernandez is unearthed, Gibbs faces a reckoning. But when he needs his team most, the loyalty of one is brought into question.

After the shocking developments in the Sandman case, the team works with the FBI to investigate further. While Wheeler struggles to hold onto his job, his family reaches a crisis point.

Vera receives an unexpected call from Bugs, who claims he's ready to answer more questions from prison after being identified as the sniper known as "Sandman." When she arrives, Bugs has suddenly changed his mind, prompting the team to reconsider the case and race against the clock to try and stop another tragedy.

The team investigates the brutal murder of a military sergeant found burned in her car, a case Franks suspects could have a connection to the assault of his estranged wife, Tish.

The team works the case of an investment advisor found dead shortly after her release from prison. Also, Mary Jo is left reeling by an unexpected development in her personal life.

The team investigates the brutal murder of a veteran who fell on hard times after serving in Vietnam, leading Franks to reflect on his own struggles following the war. Also, Gibbs considers a new path forward.

When the evidence room is broken into and significant cash goes missing, the team looks into a connection to a recent case. Also, Lala opens up to Gibbs, and Kowalski struggles to move forward.

The team investigates the death of a famed Marine commander's son, while a pivotal part of Franks' past involving his family is revealed.

As Leroy Jethro Gibbs prepares for his first Christmas without his wife and daughter, flashbacks reveal the unlikely journey that led to his first day on the job as a special agent.

The case of a missing woman who disappeared after a night of clubbing with a Navy seaman takes the team to Mexico, where they learn of a possible connection to Gibbs' past.

Gibbs and the team investigate the case of a Navy priest who was killed in the confessional booth; Randy shows Gibbs the ropes of working a protective detail.

NIS investigates the murder of a dementia-afflicted Jane Doe; flashbacks reveal the first time Gibbs met Franks.

Gibbs goes under cover for the first time with Lala as NIS works the case of a dead Navy seaman who may have been sharing top-secret intel that poses a threat to national security; Lala struggles with an unexpected development in her personal life.

With the countdown on to an execution, Franks races to extricate the location of a missing body from a death row inmate and honor a promise he made to the victim's sister before time runs out.

Still grieving the loss of his wife and daughter, Gibbs helps the team work a case involving a missing girl. The moment that irrevocably changed Gibbs' life is revealed.

A murder near Camp Pendleton leads Gibbs and the team to a suburban mall in San Diego, where Gibbs takes matters into his own hands; Jackson Gibbs pays Franks an unexpected visit.

Gibbs and the team continue their investigation.

Gibbs starts his career as a newly minted special agent at the fledgling NCIS Camp Pendleton office, where he forges his place on a gritty ragtag team led by NCIS legend Mike Franks.