Seventeen years back, enigmatic immortal beings named 'Ajin' emerged in Africa, sparking fear due to their indestructible nature and unknown intentions. Kei Nagai, a diligent high school student aspiring to be a doctor, remains oblivious to Ajin despite their societal stigma. After miraculously surviving a fatal accident, Kei discovers his own Ajin identity, thrusting him into a harrowing existence. Fleeing from a world that condemns him, Kei uncovers that fellow Ajin are nearer than he ever imagined.