From the back of the box:
HE WHO CONTROLS THE PAST
CONTROLS THE FUTURE...
Russia is in disarray, but unknowingly sits on a mineral that could see her rule the world. This mineral, Siberite, is a catalyst for Cold Fusion. America knows about Siberite and sets out to make sure that it never falls into Russian hands.
Take control of US marines sent on a one-way trip into the past to move the Siberite into American territory or command Russian troops to go back and keep it where it is. Whatever you decide, beware the Arab mercenaries who only want to see the Siberite destroyed!