Everyone would agree: Princess Marianne of the Pedin Kingdom is not a nice lady. When she slaps the daughter of Queen Orphelius, it’s an act that costs her her life. Desperate and on the brink of death, Marianne decides to summon a demon for revenge. She’s met with Yurisina, the daughter of the demon king who is eager to become a full-fledged demon by making her first contract with a human. But will the revenge Marianne asks for be too challenging for this first-time contract demon?