Pentacle Valley

A secret sect of druids built a town in a secluded woodland area of the old west. We visit them in the year 1884.

When the peace and safety of their community is challenged by an outlaw gang, the sheriff and his deputy must deal with the challenge. The sheriff deputizes a posse to assist. Some of them are killed in a shoot out.

Meanwhile, in another universe it is 2784. Their 2784 doppelgangers are the chairman and vice chairman of the Board of Engineers, a division of the Planetary Alliance for Technological Advancement.

They need to take gold and silver from the past. They can't take it from mines without the risk of earlier depletion, which could set their progress back, to the point that they would lack the technology to go to the past. This would create a paradox.

They consider past disasters, which occurred as a result of people creating paradoxes in other universes, farther back on the timeline.

The world's supplies of silver and gold had been almost entirely depleted, because all modern technologies had become dependent on the unique subatomic structures of gold and silver.

They teleport into a train car during a train robbery, while the sheriff and his deputies are having a shootout with the train robbers, and take some gold and silver coins.

Then they learn that they have an even greater problem, which requires them to meet face-to-face with their doppelgangers in 1884, and confide in them.