Sumire Takahana is a seemingly normal school girl cursed with the ability to see malevolent ghosts known as Viruses. Her life hits a crossroads after a run-in with a gothic lolita-clad monster killer for hire, Lucia Nahashia. Not content to stay on the sidelines while these Viruses prey on the weak, Sumire reluctantly decides to join forces with the mysterious, eye patch-wearing Lucia to hunt down these Viruses before they can hurt anyone else.