Serbia responds to Austria-Hungary's ultimatum after the assassination of Archduke Franz Ferdinand, and the pretext for war grows thinner and thinner. Caught between a rock and a hard place, Austrian Foreign Minister Leopold Berchtold makes a desperate decision to declare war. Kaiser Wilhelm of Germany and Czar Nicholas II of Russia call upon their family ties to each other in a last ditch effort to avert the war, but their previous inattention has left their prime ministers Bethmann-Hollweg and Sazonov in impossible positions. With their forces mobilized, unable to back down, Russia must accept Germany's declaration of war from ambassador Pourtalès - and as our series ends, the Seminal Catastrophe begins.