Based on

Movies like Sun Metal Shadow Signs (2018)

A remote camp of treasure seekers in the Mojave Desert devote themselves to the pursuit of a legendary underground river of gold. They survey the land for Spanish treasure signs and pour over film footage, affidavits, topographical renderings, amateur drawings, land and mineral claims. The gold, as yet unfound, remains an elusive material and calls forth the determination and delusion of yearning predecessors and future speculators.