Felicita grew up in a remote place with only her mother Sumire and their servant Luca for company. When she turns sixteen, her father Mondo—who heads the vigilante organization Arcana Famiglia—invites her to come live with the family. She has wanted exactly this for as long as she can remember: a real family, together. She takes her first steps as a member of the organization, and the story picks up three months later, on April 1st.