Ajin are humans that cannot die. They are caught and tested upon in secret by the government.
Kai Nagai is a high school student who discovers he is an Ajin when he is hit by a truck and survives. He soon finds himself being hunted by the government who want to use him for their research. With the help of his friend, Kaito, Kai attempts to evade capture while trying to find out more about his mysterious condition. Along the way, he meets other Ajin and learns more about the unique abilities they possess. As Kai struggles to survive and protect those he cares about, he must also confront the truth of what it means to be an immortal Ajin in a world that fears them.
