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 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.

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.

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

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".

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

After Tennant passes her medical and psych evaluations, she's surprised to see Sam's 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.

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.

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 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.