In an imaginary age of gods about 20 years after the war, Japan is flooded with all the superhumans ever written about in fictional stories: titans from outer space, lifeforms from a mystical world, phantoms and goblins from ancient times, cyborgs created by scientists, relics that rose out of the ruins of ancient civilizations, and the list goes on. Some of them make no secret of their existence and have gained popularity in the society, while others cloak their identities and fight in secrecy.

Naturally, the Japanese government cannot ignore the existence of these superhumans and establishes an organization under the Ministry of Health and Welfare - the Overpopulation Research Laboratory, a.k.a. the Superhuman Bureau. Their mission is to identify and approach superhumans, then oversee and safeguard them.