Special Agent Tennant's team, along with NCIS agents Nick Torres and Jessica Knight, learn about plans for an attack in Oahu on RIMPAC (Rim of the Pacific); the world's largest international maritime warfare exercise.
Marine staff sergeant found dead in junkyard, investigation leads to illegal street racing underworld. Tennant suspects Alex is hiding something, Whistler anxious to introduce Lucy to co-workers.
Tennant and the NCIS team suspect foul play when they investigate a fatal car crash involving a Navy officer who turns out to be an impostor. Whistler finds herself in danger when she goes undercover to learn the truth behind the accident.
When a Navy sailor washes up dead in a sacred, forbidden kapu site, the NCIS team brings CGIS Special Agent Pike to unmask the mystery and catch a possible serial killer on the island. Also, Tennant meets Alex's new girlfriend.
The NCIS team investigates the death of a Navy sailor and goes head-to-head with a ruthless local criminal organization. Also, Lucy looks for a new apartment.
A Marine Corporal dies in a tide pool after being exposed to fentanyl, the NCIS team must quickly find the source of the drugs. Alex talks to his parents about taking a gap year and Ernie reveals personal news to Lucy.
A naval officer is murdered while moonlighting in community theater, the NCIS team recruits a familiar face to help lead them to a ruthless international killer. Kai enlists Whistler to investigate an old friend turned criminal.
When Special Agent Pike is ambushed while working undercover with a local Japanese crime family, the team must find the person responsible for orchestrating the attacks.
Following a close call at a meth lab explosion, the NCIS team learn one of their own is being targeted. Lucy gets her first big case aboard her aircraft carrier.
When the murder of a captain and his wife echoes a previous case, the NCIS team brings in a former team member to help determine if they are dealing with a copycat killer.
A Navy deserter accidentally comes out of hiding, his family becomes a target that drives the NCIS team and Charlie 1 to investigate who is after them. Lucy surprises the team by returning to Hawai'i from her agent afloat job early.
A Navy residents discover their vehicles were burglarized overnight, the NCIS team connects it to a series of peculiar crimes and tracks down. Whistler struggles with an uncooperative CI and Alex weighs his college options.
Captain Milius returns to Hawai'i as the NCIS team works to catch a dangerous high-value U.S. Government target with the help of an informant unlike any they've ever encountered.
When Tennant interrogates a suspect during his helicopter transfer and the helicopter crashes, she must utilize her skills to save herself and the other passengers.
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.
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.