The French plan to respond to a German offensive was a counteroffensive into the German center. The French attempted this on August 21-23; it was an utter failure.
The outbreak of the Great War saw one of the German Navy's newest and most powerful battlecruisers in the Mediterranean. She was a threat to the Entente and had to be stopped. Only...what exactly is she trying to do?
The German war plan called for a massive offensive against France that would pass through Belgium, but one of the big unknowns in German war planning was whether the Belgians would resist, and if so, how fiercely.