This is a world where "Jewel-sama" are born with jewels in their eyes and special abilities. They live in a vast mansion called the "Jewel Box," and their duty is to grant people's wishes. The new arrival at the Jewel Box is Yuni, a girl with iron ore in her eyes, who is far from a beautiful jewel. Although she started her life as a "Master Jewel," she was not able to help people as much as she would like. Then she meets Alecrea, a master jeweler who is rumored to be a "Jewel Killer," he seems to be pursuing the unknown dark side of the jewelry box. In order to get closer to the truth, Yuni helps Alecrea and meets various other jewelry masters. Little does she know that she herself will eventually become the one to change the world. Follow your wishes and uncover the truth of the beautiful jewel box world. The unpredictable buddy and love fantasy between a girl with black iron and a rebellious young man begins! 瞳に宝石を宿し、特殊な能力を持つ「宝石様」が生まれる世界。 宝石様は「宝石箱」と呼ばれる広大な屋敷に住み、人々の願いを叶えることを務めとしている。 新たに宝石箱へやって来たのは、美しい宝石とは程遠い、鉄鉱石を瞳に宿した少女・ユニ。 宝石様として暮らし始めたものの、思うように人の役に立つことができないでいた。 そんななか出会った、「宝石殺し」と噂される宝石様・アレクレアは、 宝石箱の知られざる闇を追っているようで――？ 共に真実に近づくため、ユニはアレクレアを手助けしながら、様々な宝石様に出会っていく。 やがて自身が、世界を変える存在になるとは、まだ知らずに……。 願いをたどり 、美しき宝石箱〈せかい〉の真実を暴け。 黒鉄の少女×反逆の美青年　予測不能のバディ＆ラブファンタジー、開幕！