During World War 2, the Nazis experimented with breach the barriers involving the three worlds. They failed then, but a Dr. Myunihausen (Munchausen?) tries again, through the manipulation of Nagumo's brother Takeaki. His goal? To have the Chojin replaced.

As Takeaki is injured from the approaching flight, Nagumo donates his blood to save his life, thus infusing Takeaki with the powers with the overfiend. And the results might be a lot of for Tokyo, it mat be the overfiend himself, to deal with.