Officially, no open conflict broke between the superpowers during the cold war. However, starting immediately after WW2, both sides began research into trans-dimensional portals based on secret research documents captured in Nazi Germany.

In 1968, both powers separately succeeded in opening a trans-dimensional gateway. After various expeditionary missions, each began harvesting the vast natural and mineral resources of the new world. Inevitably, this brought them into conflict with each other, as well as the locals...