A Navy lieutenant, otherwise in perfect health, dies in his car while madly trying to reach an emergency room at a hospital; Gibbs and company investigate; Tony gladly volunteers to interview the victim's sister, who's an attractive reporter on a cable news network; when he and Ziva arrive, they find that someone has tossed her pad. The sister has disappeared. The vic worked on a classified program at the Navy Info-ops Center (NIOC); Tony has a contact at the NIOC, so Gibbs asks him to use it. A long-time friend of the siblings recently died, supposedly by accident; Gibbs comments on the "coincidences". Palmer finds a key piece of evidence with a sinister implication, and Ducky finds another one. Ziva says that Tony has become obsessed with the sister; he eventually finds her; with her help the gang put the puzzle together. Gibbs and Ziva bust the killer.