Legend says that the Aztecs hid a vast fortune in gold in the American southwest 500 years ago. Today, three families search for where they believe this treasure to be, each following their own set of clues.

The Dillman Family completes the underwater dye test at Shadow Cave. In Nevada, the Miners bring in a Cave ROV so they can explore past the dangerous mine collapse.

The Miners in Nevada use a smoke gun to find another entrance to a dangerous tunnel system. In New Mexico, the Villescas family uses crossbow ingenuity to find their way into a sketchy mine.

The Dillman family seeks answers in the mysterious Weeping Cave. Meanwhile, the Villescas family builds a shaker box to help sift through material faster.

The Villescas talk with an expert about whether a spur they found could tie to the Conquistadors. In Nevada, the Miners' search gets sidetracked by the discovery of a potential grave site.

The Villescas family risks it all in New Mexico by bringing in more heavy machinery and a full crew. In Nevada, the Miners' research is threatened by the Sheriff's Department.

In Utah, the Dillman family drills into what they believe could be the hidden treasure chamber that their grandfather predicted; after a close encounter, the gold miners in Nevada must find another way into the rest of the underground tunnel system.