Tennant and NCIS must take down a notorious team of international thieves before they complete their final big job and disappear; Kai searches for a new place to live; Lucy and Whistler have a standoff about their previous encounter.
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.
When Tennant and NCIS are tasked with finding a kidnapped social media star, they find that she is not who her husband, or her followers, think she is; the team is at odds with Whistler, who has an agenda of her own.
NCIS investigates the mysterious death of a Navy engineer; Jane's mentor and friend is kidnapped; a New Zealand intelligence service case officer arrives and connects the Navy engineer's death to a Chinese black operation secret agent.
Captain Milius continues to work with Tennant and her team in the aftermath of the prisoner exchange between U.S. and Eastern Europe; Whistler takes Ernie's advice and makes a grand gesture in hopes of winning back Lucy.