"Welcome to Venus Vangard. We've been expecting you."

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 decides to join forces with the mysterious eyepatch-wearing Lucia to hunt down these "Viruses" before they can hurt anyone else.