Sumire Takahana was a seemingly normal school girl cursed with the ability to see malevolent ghosts know as "Viruses". But her life comes to a dramatic crossroads after a run-in with a Gothic Lolita-clad monster killer named Lucia Nahashia. Not content to stay on the sidelines while these Viruses prey on the weak, Sumire decides to join forces with the mysterious eyepatch-wearing Lucia to hunt down the Viruses before they can hurt anyone else.