In the original manga's story, an immortal first appeared on an African battlefield 17 years ago. Later, rare, unknown new immortal lifeforms began appearing among humans, and they became known as "Ajin" (demi-humans). Just before summer vacation, a Japanese high school student named Kei Nagai is instantly killed in a traffic accident on his way home from school. However, he is revived, and a price is placed on his head. Thus begins a boy's life on the run from all of humankind.