Legend has it that five hundred years ago a vast fortune in gold was hidden by the Aztecs somewhere in the American southwest. Now three families are closing in on what they believe is the location of the treasure.

The Dillman Family continue their grandfather's 56-year search by completing the underwater dye test at Shadow Cave, which may reveal more than they bargained for.

The hunt begins to heat up when the Miners in Nevada use a smoke gun to find another entrance to this dangerous tunnel system. In Utah, the Dillman family dig up the mysterious marsh, which may have previously revealed an ancient artifact.

The Dillman family seeks answers in the mysterious Weeping Cave, and in Nevada, the miners bring in an expert to examine a very unusual discovery from the mine.

The Villescas family seeks expert advice about whether a spur they found might be tied to the Conquistadors. The Dillmans use drones to locate an important ancient symbol, which could be a map.

In New Mexico, the Villescas family gamble everything by bringing in more heavy machinery and a full crew for one last push to unearth Conquistador gold.

In Utah, the Dillman family drill into what they believe could be the treasure chamber. The Miners in Nevada must find a way into the tunnels. Meanwhile, the Villescas make an underground discovery.

In Utah, the Dillmans must be careful not to trigger an Aztec water trap while digging deep into the cave chamber. In New Mexico, the Villescas family discovers that there are more secrets buried beneath the Fire Pits.