A Student named Kei Nagai, who discovers he is an "Ajin" when he is fatally wounded in a traffic accident. In the world of Ajin, a small number of humans possess extreme regenerative abilities that trigger upon death or mortal infury, allow them to completely recover from their woulds in a matter of seconds. Kei, who wants no part in the emerging Ajin-human conflict. Agree with Japanese govermental againts to fight against Satou in exchange for his freedom from government experimentation.