Total Annihilation is made by Cavedog Entertainment and is the best strategy game I know.  I dont exactly know the plot of the game but its fun.  There are two races, even though they aren't really races, I consider them to be because they have different units.  Speaking of units, there are too many too count.  There are more units with just these two sides then there are with the three races in Starcraft.  With the expansion set, Core Contingency, its just overkill.  Just the two groups' units alone are more numerous than Starcraft's units and buildings for all three races including the expansion set.  This is a must buy for anyone even remotely interested in strategy games.