NCIS is called in to investigate when a lieutenant returns home on Halloween Eve to find a surprise party being thrown for someone else at his home.

As Vance prepares to host diplomatic talks with Venezuela, the team is called in to investigate the dead body of one of his inside men.

NCIS searches for a missing undercover agent in the midst of an active hostage situation.

Parker and Knight discover three bodies on an old Navy ship that's about to be sunk and turned into an artificial reef, when they're suddenly locked inside by a mysterious figure. Also, Vance offers Knight a unique opportunity.

NCIS team looks for a motive behind the kidnapping and death of a famous heart surgeon.

NCIS comes under attack by a mysterious enemy from the past; Vance tries to mend fences with his estranged son by explaining why, despite the ongoing dangers of his job, he still chooses to stay at NCIS.

After discovering a Navy pilot's body riddled with unusual wounds, NCIS' investigation draws the team into the rabbit hole of UFO conspiracy theories.

With the help of Knight's dad, special agent Feng Zhao, NCIS works to unravel the mystery of a recently used service weapon belonging to a missing agent; McGee is in a tailspin when DNA results reveal a close relative he was unaware of.

When the NCIS team engages in Walk-a-Mile day to gain a new perspectives on different departments, things take a turn when Kasie receives a distress call from a mysterious man.

As NCIS mourns the loss of Ducky, the agents find comfort in working on one of his unfinished cases involving a woman whose father was dishonorably discharged from the Marines.

The NCIS team must help Torres when he puts his future at stake by confronting the man who tormented his family when he was a child.