n Africa, a mysterious group called "Ajin" appeared seventeen years ago. Possessing indestructible bodies and potential for evil, they were viewed as a threat to humanity and quickly captured if found in society. Kei Nagai had only heard of them through news reports, although his high school taught him not to see Ajin as human. As a studious student aiming for medicine, he ignored the topic. Yet, after a fatal accident that inexplicably transformed him into an Ajin, Kei found his limited knowledge insufficient to face his new existence alone while avoiding detection. Gradually, he realized that more Ajin might be closer than he once thought