When a figure from Tennant's CIA past re-emerges, the NCIS team seeks help from the most unlikely place to catch a killer who threatens to destroy everything Tennant has built.
Sig returns from his mother's funeral only to find his gear in harm's way. Rick and Keith forge a beneficial partnership. Jack makes his first offload as captain. The Coast Guard gets a call to extract a sailor with broken legs 200 miles out to sea.
The discovery of a dead former MI6 agent uncovers secrets from Tennant's past, forcing her to go to extreme lengths to track down the responsible party.
When a suspicious murder occurs in the classified section of the National Archive, NCIS must investigate a string of Russian spy encounters that may be linked to the crime. Also, Jimmy accidentally makes a confession that could change the course of his relationship with Knight.
The team works with the DEA and their iron-jawed leader, Mack Boyle, to stop a ruthless cartel boss waging war on the streets of Los Angeles as he exacts revenge on those who killed his son.
SWAT teams up with the DEA, led by Mack Boyle, to conduct a massive gang sweep, only to discover that a vicious cartel is planting roots in the city and endangering numerous lives. Also, Hicks marks an important anniversary.
A new deckhand falls ill on the Time Bandit, raising questions for Andy and warning signs for John. A bait pallet breaks loose, forcing Captain Rick to deal with a severe crew injury. When Wild Bill's plan A fails on the Summer Bay, Maria tries plan P.
NCIS works to solve the murder of a senator’s daughter who has a rebellious reputation and large online following. Also, Jimmy gets competitive with an old college rival.
When an ATF agent goes missing, the agency seeks help from the NCIS team to investigate stolen military-grade weapons and locate the agent. Also, Callen and Anna continue to plan their wedding, Rountree’s sister interviews for medical school and Sam encourages his father to take part in the drug trial.
Sig buries his beloved mother and the last of his family's pioneering generation. Sean Dwyer joins forces with Rick Shelford but the two captains don't see eye to eye on rules. Jacob fights back on the Wizard and finds no safe harbor from Captain Keith.
Sig gets tough news at sea forcing the Hansens to make a critical decision as John and Andy lend a hand. With wheelhouse ambitions, Jacob hits a wall with Keith on the Wizard. New captain Jack crosses a line when Harley makes a deal with Jake.
When four people, including a CIA officer, are shot and killed in broad daylight, the NCIS team suspects the attacks have something to do with DRONA. Also, Pembrook meets with Callen and gives more insight into his past.