Mac arrives at Harm's apartment and is surprised to see that he has forgotten she was coming over and that he is getting to leave with a firearm. Stalling him, she gets him to tell her the story 2 years ago of the murder of his then-girlfriend, Lt. Diane Schonke, an Academy classmate, after her ship, the USS Seahawk docked in Norfolk. When Harm shows Mac a picture of Diane, Mac is stunned to see that Diane looks just like her.

NOVA follows an international team of archaeologists and spelunkers into the Rio la Venta Gorge deep in the Chiapas jungle of Central America. In a rugged canyon they find caves filled with startling remains of a people called the Zoque who lived hundreds of years before the Maya. The extreme inaccessibility and relative dryness of the caves has preserved rare artifacts including bones, clothes, rope, and jewelry. Moving downstream from the caves the team finds a legendary city hidden in a tangle of jungle vines. Evidence of the Zoque's sophisticated writing system and their practice of ritualistic cannibalism and child sacrifice is shedding new light on a little known civilization.

More bloodhound units arrive and the fight with the violent faction of Byron's followers intensifies... until the rogues seize medlab - with Garibaldi and Franklin in it.