When Erina gets adopted by Marquess Sinor because of her magic abilities, she didn't realize her life was only about to get much worse. After years of abuse and torment from the Marquess, Erina is on the verge of breaking down. Just when she decides to end it all, Erina is visited by her past self: Marystella, the powerful witch who once ruled the entire kingdom. Marystella asks Erina if she could help her reveal the truth behind her death.