Norio, an ordinary high school student, becomes the undesired target of romantic advances. However, a chance encounter with an attractive stranger after tumbling down the stairs reveals an astounding reality that he couldn't have fathomed. Norio stumbles upon a clandestine community of "exceptional" humans, descended from non-primate animals, and shockingly realizes that he belongs to a highly uncommon lineage. Now, Norio is the hunted, and he must tread cautiously through this unknown territory if he wishes to survive. The world is akin to a contemporary jungle, and Norio must utilize all of his intelligence to endure.