When a petty officer is found murdered, Gibbs learns about the mysterious connection between the disbanding of his team and the case.

The body of a Marine leads Gibbs and McGee to the NCIS OSP division in Los Angeles, where a murder investigation quickly climbs to a matter of national security in which the two offices must work together to resolve. Meanwhile, Tony begins to snoop into Ziva's personal life.

With the appearance of Mossad agent Michael Rivkin, Tony is forced to question Ziva’s loyalty to NCIS. Meanwhile, in Los Angeles, Special Agent Callen goes undercover to try to catch a terrorist cell while OSP psychologist Nate Getz discovers the startling truth about Gibbs and Special Agent Lara Macy’s relationship.

After a security breach at the SecNav's residence leads to the death of an ICE agent, Gibbs and the team are forced to work with ICE and the FBI to find his killer. Meanwhile, Tony finally comes face-to-face with Michael Rivkin.

Ziva's homecoming to Israel with Gibbs and the team is not a happy reunion with her father, the enigmatic and powerful head of Mossad. As tensions rise, Gibbs is forced to make a decision that sends shock waves through NCIS.