The story follows a high-school student named Kei Nagai who is caught in a traffic accident, dies, but immediately revives and learns he is not human, but an Ajin, a mysterious creature that cannot die. Scared, he runs away from humans hunting him down but is helped by his friend, Kai, who joins him in his flight from civilization. He then becomes involved in a conflict between human and Ajin and must choose a side.

Note: Only the first volume is credited to .

Nominated for the 7th annual Manga Taishou Award, the Readers Award in the 18th Tezuka Osamu Cultural Prize, the 38th Annual Kodansha Manga Awards in the Seinen category and the 40th Kodansha Manga Awards in 2016 in the General category.