A new infection has spread around the planet, that turns people into undead. The story begins a few minutes before the first recorded case, and shows the struggle of six youths to survive this new world.

As a baby Jiro was delivered to his foster parents by a massive oni, who said he would return for Jiro in 15 years. When the time comes Jiro must contend with enemy oni, dark cultists, and their minions while...