With the advent of people of Japan suffering from an incurable mutagenic disease dubbed as the "deathless syndrome", some people became incapable of dying by any and every normal means. Boasting incredibly high regenerative qualities these people became effectively immortal.

Codename Grave is a drafted member of the taskforce named 'Death tenders' for the Tokyo division R34P3R initiative. This taskforce is a group comprised of individuals with the sole unique ability to be able to kill those suffering from the syndrome.

Tasked with the elimination of afflicted individuals in an effort to 'Cull the herd' he and his supervisor Whiro were on grave's last case before reaching his civilian quota allowing him to do what he always wanted to do.

To cut loose.