Kenzou Tenma, a celebrated Japanese brain surgeon practicing in post-war Germany, faces a moral dilemma: operate on Johan Liebert, a dying orphan boy, or prioritize the mayor of Düsseldorf. Opting to rescue Johan at the cost of the mayor's life, Tenma risks his career and reputation. Subsequently, he endures the loss of his job and his fiancée, Eva, as a result. Amidst his downfall, a twist of fate occurs when Heinemann, the hospital director, meets a sudden demise, offering Tenma a shot at redemption. Fast forward nine years, Tenma rises to lead the surgical department, poised for the directorship. However, his tranquility shatters as a series of brutal murders grip Germany, all linked to a sinister force—the same entity he once saved, now turned malevolent.