A girl who admired adventurers awakens as a "vampire" when she is attacked by monsters and nearly dies.

Erika Trainan was helped by an adventurer when she was young and became an adventurer herself, yearning to be like them. Though she lacked talent, she wished to become like the adventurer who had saved her—and she found herself wandering the brink of death, attacked by a horde of monsters. When she opened her eyes again, she was in an unfamiliar place, and a young girl spoke to her. "I am Claire Vermillion—a vampire." Claire forces Erika to make a choice.