Several years later, at a UN military base in Bosnia, multinational soldiers are guarding a forensic team excavating a huge mass grave, which satellite imagery shows being disturbed every night. The soldiers first assume that Serb soldiers are trying to destroy the evidence of their atrocities; a US Army Aviation officer named Elias Branch leads a reconnaissance-helicopter flight to gather evidence. After a crash, he finds his navigator brutally assaulted, is menaced by an unseen enemy, and is himself badly injured by his unit's supporting fire. Found scarred and half-mad, he raves about being attacked by "demons;" during his recuperation, he begins to exhibit dramatic physical changes, and begins taking an interest in local cave systems.