A Marine sergeant dies, apparently from a fall, in the Shenandoah River State Park, near Bentonville, Virginia, while hiking with his wife and his best friend, another sergeant; Gibbs and company investigate. Ducky finds a wood-fiber fragment in the victim's scalp, Abby identifies it, and Gibbs interprets the identification. The victim used a videocamera, which McGee finds, and from which Abby recovers recent footage; she puts together what she calls a nature documentary with a riveting murder-mystery subplot with an alternate ending. McGee encounters leaves of three, and Gibbs and Kate find and chase a suspect. Gibbs and Kate take the widow and the best friend to different chat rooms, then to the same one. The team figure it out, and Kate adopts a pet.
—DocRushing