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
atrocities
Bosnian genocide
The Descent (novel)