L'ispettore portuale Goodrick viene trovato ucciso in un container contenente due casse di armi. Intanto, Tennat deve risolvere anche una delicata questione di famiglia.

L'N.C.I.S. indaga sull'omicidio di due agenti dell'F.B.I. e di due uomini che utilizzavano il ristorante Ho'olua per riciclare denaro sporco.

La squadra NCIS indaga su un naufragio di una nave che trasportava animali esotici e che ora mette a rischio la fauna selvatica di Oahu. Alex subisce un infortunio che mette fine alla sua carriera e Kai chiede a Melanie un appuntamento.

The NCIS team's investigation takes them deep into the world of illegal street racing after a Marine staff sergeant's body is discovered in a junkyard. Also, Tennant is concerned Alex is hiding something from her, and Whistler is anxious about introducing Lucy to her co-workers.

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.

When 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; Ernie reveals personal news to Lucy.

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. Also, Tennant and Daniel deal with Alex’s acceptance into the Naval Academy