Miu Sakurai, age 15, attends a Catholic school where she prays every day for her admired Shion Amamiya to return her love. When that doesn't work, she places her faith in a book of magic and tries casting one of its spells. However, it's not love that manifests... it's Satan! "The recompense for the contract to grant your wish is your virginity," he tells her, and this is Miu's virgin crisis!