This game depicts the German blitzkrieg campaign against Poland in September, 1939. Historically, it was a stunning victory but the blitzkrieg strategy was untested and the potential was present for Poland to hold on long enough for other countries to intervene against Germany.
In the game, the German side needs to force the Polish surrender quickly. This occurs by capturing the Polish capital, Warsaw, and other Polish rallying points. The Polish side needs to delay the German advance long enough to garner international intervention. This occurs when the Polish win three delaying actions.