After the U.S. Treasury Department is hacked, Nell and Eric go undercover inside a couple’s retreat to track a tech-savvy husband and wife linked to the crime. Also, Digital Forensics Specialist Dave Flynn (Scott Grimes) arrives from the NCIS cyber office in San Diego to run ops while Eric and Nell are on assignment.

Sam resumes an old alias to bring down a major criminal kingpin; Callen and Anna’s romantic night is interrupted when they are tasked with escorting a high-value prisoner to Los Angeles for questioning.

When a Navy lieutenant and his grandfather are kidnapped from a retirement home, the team’s investigation leads them to a con artist couple and the hunt for a rare coin; Callen meanwhile has to deal with his father’s actions when he kidnaps the father of his grandson (and Callen’s nephew).

As the team races to save Kensi from Ferris/Sullivan, they find themselves questioning who they can trust when old faces resurface.

Hetty goes rogue, leaving the NCIS team completely in the dark, and the mole kidnaps one of the agents.

The mole has once again compromised the NCIS team as planted evidence results in the arrests of Callen, Sam, Granger and Deeks, on the day Under Secretary Duggan (Jackson Hurst) returns for Hetty’s resignation.

After a Navy reservist is killed while protecting a city councilman, Sam is sent undercover in a private security firm with links to several criminal organizations.