Following a devastating ambush with a deadly bioweapon, the NCIS team must track down a mysterious terrorist group before they can strike again.

When a high-value bioweapons expert is murdered in a secure facility on Hawai'i, NCIS and the NCIS Elite team join forces to track down the killer and discover an even deadlier threat.

After a Marine's wife is kidnapped for ransom, the NCIS team uncovers dark secrets as they race to track down her abductor before it's too late. Meanwhile, Sam seeks Ernie's expertise decrypting a computer program that may have deadly ramifications.

When a Marine is murdered during training on the Big Island, the NCIS team tracks the suspect deep into the woods and discovers a disturbing secret.

When the fiancée of a vanished naval officer seeks the help of NCIS, the team reveals his secrets go much deeper than she suspected. Meanwhile, Sam recruits Kai to be his wingman.

NCIS is tasked to protect the daughter of a Russian oligarch carrying a deadly secret. Meanwhile, Sam asks Tennant for a favor.

When a Navy pilot is found murdered at a local military resort, the team goes undercover to discover a criminal enterprise hiding in plain sight.

After a brazen daytime robbery of a Navy Federal Credit Union, the NCIS team tracks down a group of adrenaline-seeking thieves. Meanwhile, Tennant grows suspicious of Sam Hanna's reasons for being in Hawai'i.

Following the crash of a prisoner transport plane, the NCIS team must find the convicts that escaped onto the island. Meanwhile, Sam Hanna and Tennant are tasked with locating a high-profile Russian prisoner known as "The Chemist."

After passing her medical and psych evaluations, Tennant is surprised to see Sam Hanna conducting her final interview to clear her return to work. Also, when the team discovers a breach in the U.S. Marshal's database, Sam joins Tennant in Las Vegas to locate the hacker.