After investigating Vance's car, the team locates Vance at a family plot where Vance finds himself next to the body of a sailor killed along with Dearing's son. After picking him up, the team finds another message with a horse jaw that leads them to a retired NCIS agent who handled a case that sent Dearing's son to the destroyer that claimed his life.
However, Dearing blows up the agent's house and leaves them a message, soon confronting Dr. Ryan by threatening her son and forcing her to flee when he bails out her jailed ex-husband.
Meanwhile, Jimmy is nervous on whether or not to marry with all of this, but Ducky tells him to go through with it, and he will join him, and Jimmy asks Breena to advance the wedding so he could return. Gibbs recruits Cole based on Ryan's profiling of Dearing to lure him into a trap, but Dearing avoids it and leaves a phone call on the Navy Yard.
Playing the call makes the team realize there is a bomb in Vance's car, installed when he was abducted, and the whole building is evacuated. Cole attempts to defuse the bomb, but he is blown up as well as damaging much of the NCIS building.
Ducky receives a phone call about the attack and is asked to autopsy the bodies, but soon suffers a heart attack after the message, leaving everyone's fates unknown.