Doors to infinity. The little glass spheres looked as innocent as children's marbles. But they were the keys that unlocked another world—a world that threatened life as we know it on Earth and could ultimately destroy the universe itself. And the vanishing of a kid gang was the first step... Professor John Zanthar wasn't on Earth at the beginning. He was exploring the moon with a small group of Space Marines. And he found an impossible city—a city ancient beyond the dreams of man, living on where no city could possibly exist. A city ruled by mutant women who hated all men and wanted to destroy them! He found, too, that the city had already been invaded by his old enemy Fu Cong, who sought control of the mutant powers to further his own dreams of conquest. And once again, Zanthar went bravely into battle—against forces even he, with his fantastic scientific knowledge, could barely understand!