When two burglars enter a home in Arlington, Virginia, in the burbs of Washington, DC, they find the hanged body of a man; the victim proves to be that of a psychologist (with a PhD degree), who was also a Naval Reservist on active duty, and who held a high-level security clearance for his work, which included consulting with the US Department of Defense (DoD) on a psy-ops program; while Gibbs and company investigate, they soon encounter Dr. Rachel Cranston, who was a colleague of the victim, and with whom they've dealt before. Another mind-gamer shows up, and Abby finds a mind game. McGee plays with some electronic toys, and the other members of the gang pursuit other leads; Gibbs orders the team to concentrate on paper, and he kills a bug. Despite much interference and misinformation, the gang solve the puzzle and bust the people responsible. A payroll clerk discovers a number of mistakes, and Gibbs receives an interesting phone call at 04:00.

While Gibbs and Tony man a protective detail for the SecNav, a gunman shoots the secretary; the NCIS investigates quietly with the help of Dr. Ryan. Blackmail is involved; the gang and Ryan figure it out and find a hacker and the bad guy.

A picnicking couple encounter a dead body, which proves to be that of a first lieutenant in the US Marine Corps; after Gibbs chats with Dr. Ryan, he and the team investigate; the gang see that the victim had plummeted from somewhere in the sky after he had first been beaten, stabbed, and shot; in one of his pockets they find a challenge coin, which they trace to a woman commander in the Navy Chaplain Corps, who is on duty with a relief team in Colombia. Ducky finds curious clues, and Abby interprets them (connecting to Colombia); Ziva communicates with Monique, a contact in Colombia, who repeats a rumor about the disappearance of the Marine and the chaplain; Ryan gives Gibbs a tip. Tony, Ziva, and a second woman chaplain join Monique in Colombia; someone else provides fireworks; then Gibbs interviews a mule. McGee continues to dig, then Ziva and Monique meet a couple and get answers. Tony, Ziva, and two chaplains fly back home with their new friends.

Dorneget gets a surprise from a dentist; Gibbs and company continue to investigate Dearing and the thermite incidents. Dearing visits the Navy Yard and messes with Gibbs. Moves and countermoves abound; Vance disappears. [Continued.]

Gibbs and the gang continue to pursue Dearing, the explosions, and the disappearance of the director; Dearing continues to mess with Gibbs and Ryan. After another explosion and another death, disaster strikes at the Navy Yard. [Continued.]