Upon entering the Ortigia Academy of Magic, Alto Goldfilled set his sights on one goal: to become a master sorcerer. Despite his impeccable grades and dedication to his courses, Alto struggles with one particular aspect of his studies: summoning class. He is in danger of failing and is faced with the possibility of repeating a year. Desperate for a solution, Alto turns to an old and tattered grimoire that he hopes will provide an answer. Much to his surprise, Alto manages to successfully summon a powerful demon named Vermeil. In gratitude for her release, Vermeil agrees to be Alto's familiar and seals the pact with a passionate kiss. However, Alto is completely unaware of the true extent of his abilities, and he knows nothing of Vermeil's cryptic past.