Resistance/The New Order Crossover
(A random idea of Resistance mix with The New Order: Last Days of Europe.)
It started in the East, on the old Polish border with the Russian Empire and their massive wall. From the Baltic to the Black Sea, and longer than the Chinese Great Wall, the Curtain kept all outsides out and all of the Russian citizenry in as Russia disappeared into extreme isolation.
When Poland fell in 39, many attempted to jump the barrier to escape the Nazi onslaught or beg Tsarist border guards to help them. Many were shot, killed by landmines, and other traps, and those who did escape onto the other side was never seen from again. Even Hitler was uneasy at the Red Curtain and the Russian mystery, but for all intents and purposes the Axis Eastern flake was secured and against all odds Germany and its allies gain victory in the Second World War.
And while basking in their victory, the Chimera broke through the Russian barrier. Berlin immediately knew something was wrong when everything east of them went dark. The Eastern pride of the Reich were wiped off the map. The Nazi High Command, thinking that that Slavic hordes had finally revealed themselves, rush to defend the German Reich conquests and broadcast it to the world.
They lasted hours to a couple of days.
Adolf Hitler, the man who had lead the German Reich to a unpredictable victory over the world Superpowers, saw his life work fall into ruin and become a living nightmare, slipped into fits of rage, and fury and sheer delusion. It not actually known what happened to him, only he had refused to leave Berlin when it fell.
The Führer gone, the knives came out, as his confidants and Inner Circle fought each other in a petty war of succession, even as the Chimera sweep across Europe like an undying plague. A insane Himmler and Heydrich would use Germany limited nuclear arsenal in their Ragnarök, bombing everything they still could from the Rhineland to the Low Country to France. It was reported that the Chimera simply bombed everything in Nancy and around to a landscape more alike to the Moon or WW1 No Man's Land.
Hermann Göring fled to the African colonies, Speer fled to the United States as head of an exile government. No one knew the fate of Bormann other than fleeing deep into the Austria Alps.
Cities home to millions became empty, no one escaped or a thousand or so souls. And the Nazi allies very soon follow their masters into the grave or worst.
Many veterans of the war fought like mad men, or took their own lives, knowing what the Chimera did to you. Uneasy and bitter alliances were formed. Those who could fled to Africa or anywhere else. The victors reduced to exile and refugees.
The conquered British Isles found itself all alone as Europe burned and went dark. Edward VIII went on the radio day and night, proclaiming Great Britain shall and win triumph over this new darkest hour, even as the collaborationist government and trapped German Army fought tooth and nail against the resistance.
The newly elected President Eisenhower, their worst fears finally realizing. Ever since that tower was found in Nevada, the Special Research Projects Administration or SRPA was founded to search and recover alien artifacts and technology and ready the United States and the Human Race for the inevitable. Even with America's defeat in the war, SRPA remain their greatest advantage, with many resources pour into it and demobilize men found themselves to report to black sites for new marching orders along with many exiles.
To save the British Isles, the Chimera digging under the channel, and the last human stronghold outside of Iceland, Operation Deliverance would see a massive landing in Scotland while airborne would land across the countryside.
God save us all.