A seller of rare books is murdered, drawing Jane and Maura into a realm of Celtic writings and coded confessions. Meanwhile, Angela's relationship with Cavanaugh begins to change.
A teenager's hacking skills get the attention of NCIS after he compromises terrorist missions.
A marine skilled in K-9 bomb detection is killed on duty in Afghanistan and his wife begs the NCIS team to conduct their own investigation.
In order to find out more information about the government's investigation into Nate's murder, Michael must help the FBI take down a Boston mobster.
The arrest of Kensi for the murder of her father's former associate leaves the NCIS team astounded and scrambling to prove her innocence.
Eric Matheson, a man accused of killing his wife, holds the Lightman Group hostage to get them to prove his innocence.