In the last moments of World War II, a secret Nazi space program evaded destruction by fleeing to the Dark Side of the Moon. During 70 years of utter secrecy, the Nazis construct a gigantic space fortress with a massive armada of flying saucers.
When American astronaut James Washington (Christopher Kirby) puts down his Lunar Lander a bit too close to the secret Nazi base, the Moon Führer (Udo Kier) decides the glorious moment of retaking the Earth has arrived sooner than expected. Washington claims the mission is just a publicity stunt for the President of the United States (Stephanie Paul), but what else could the man be but a scout for the imminent attack by Earth forces? The Fourth Reich must act!
Twenty years after the events of Iron Sky, the former Nazi Moonbase has become the last refuge of mankind. Earth was devastated by a nuclear war, but buried deep under the wasteland lies a power that could save the last of humanity - or destroy it once and for all. The truth behind the creation of mankind will be revealed when an old enemy leads our heroes on an adventure into the Hollow Earth. To save humanity they must fight the Vril, an ancient shapeshifting reptilian race and their army of dinosaurs.