A superior alien race attacks Earth at the height of World War II. After an alien invasion during World War II involving nuclear explosions in the sky, Jens Larssen travels from Chicago to a temporary United States capital to convince the U.S. that the atomic research project in Chicago must be defended. Patton is eventually called back to do just that and Jens begins a hard journey back to Chicago to try to find his wife and rejoin the lab.
The aliens came to Earth based on images they took during the Middle Ages. They are surprised at Earth's progress in what they consider a short time. The aliens explode nukes over major cities to create an electro-magnetic pulse to knock out computers. They do not realize that humans use vacuum tube tech which does not react the same to the pulse as more advanced technology would.
The Allies and Axis turn their attentions on the invading aliens. Jewish leaders try to communicate the evil of the Nazis. The Aliens take advantage of this and it is not well received by the rest of the world.
Aliens capture humans and force them to breed because human biology and processes are very different from the aliens' reptilian biology and they want to observe. The aliens ignore water based technologies and navies because they do not have large bodies of water on their planet, so they fail to see the importance. Humans take advantage of this blindspot for a while, but then the aliens change tactics.
The Chicago lab tries to move to Denver to avoid capture. Jens's wife goes too and starts a relationship with one of the soldiers thinking Jens is dead.
Despite dominating much of the world early on in fighting, the aliens start running low on advanced weapons and have to use captured factories to create low-tech, human-level weapons. They are also not prepared for even minor cold. The aliens try to attack oil fields to cripple the humans, but take heavy damage themselves.
Chicago is liberated and Jens discovers the lab has moved and he tries to reach Denver.
Best scene in story:
Patton attacking the aliens to liberate Chicago is a chilling scene showing a different World War reaching the heartland of the United States instead of being fought in other lands.
Opinion about the main character:
Jens is loyal to his country, to humanity, and to his wife. When these ideals come in conflict, he makes sacrifices and continues to fight.