機巧少女は傷つかない - 舞台は機巧魔術が隆盛を極める大英帝国の機巧都市リヴァプール。
日本からやってきた留学生・赤羽(あかばね)雷真は、
美しい少女の姿をした自動人形の夜々とともに、
魔術世界の最高学府、ヴァルプルギス王立機巧学院の門をくぐる。
目指すは機巧魔術を操る人形使いたちの頂点であり、
尊敬と畏怖の象徴である魔王の称号を得ること。
そのためには4年に一度の魔触の年に開催される《夜会》に参加し、
学院の上位成績者100人が、自動人形を使って戦うロイヤルランブルに勝ち抜かなければならない!
Machine-Doll wa Kizutsukanai (Unbreakable Machine-Doll) - The Walpurgis Royal Academy of Machinart was founded alongside the development of "Machinart," machine magic capable of giving life and intelligence to mechanical dolls subsequently called as "automaton." Its aim: train skilled puppeteers to control the automatons, as militaries across the globe have begun incorporating Machinart into their armies.
After miserably failing the academy's entrance exams, Raishin Akabane and his humanoid automaton Yaya must defeat one of the top one hundred students to earn the right to take part in the Evening Party, a fight for supremacy between puppeteers using their automatons. The last one standing is bestowed the title of "Wiseman" and granted access to the powerful forbidden arts.
Thus, Raishin challenges Charlotte Belew and her automaton Sigmund to a duel, but before they even begin, Sigmund is attacked by other students. After saving his opponents from their assaulters, Raishin cancels the duel but is forced to search for a new way to gain access to the Party. Driven by the tragedies of his past, Raishin fights alongside Yaya to rise to the top and claim the title of Wiseman.