Germany's spring 1940 offensive rolls through Denmark, Norway, Holland, Belgium, and France in a matter of weeks, and this entry in the US War Department's "Why We Fight" series lays out how Hitler's strategy of picking off nations one at a time let a numerically smaller force overrun the continent. Maps and captured German footage trace the invasions country by country, showing how neutrality declarations and divided Allied command left each nation to fall largely on its own. The film builds toward the collapse of France and the British evacuation from Dunkirk, presenting it as the near-total loss of Western Europe rather than a victory dressed up as one. As US government-produced propaganda, it argues its case directly to American audiences: the divide-and-conquer method that worked on Europe was a tactic still to be stopped, and the war was not someone else's problem. The tone is instructional and blunt, built to explain why the fight mattered to the soldiers about to be sent into it.