Plot
Dr. Kenzo Tenma is a highly skilled Japanese neurosurgeon working at Eisler Memorial Hospital in Düsseldorf, West Germany. Though professionally accomplished and engaged to Eva Heinemann, the hospital director's daughter, he becomes disillusioned with the institution's practice of prioritizing politically influential patients over those in dire need. This ethical dilemma culminates when fraternal twins Johan Liebert and Anna Liebert are admitted after a massacre, with Johan requiring emergency surgery for a gunshot wound to the head. When the mayor arrives shortly after, also in critical condition, Tenma disregards orders and operates on Johan. Though the boy survives, the mayor dies, and Tenma faces severe repercussions—his career stalls, his engagement ends, and he is ostracized by his colleagues. Soon after, Director Heinemann and several doctors who opposed Tenma are murdered, and the twins disappear. Though Tenma is suspected, no evidence links him to the crimes, leaving him to confront the consequences of his choice.
Years later, Tenma has regained his standing as Chief of Surgery. His life is upended when he treats Adolf Junkers, a criminal who cryptically warns of a "monster". Visiting Junkers later, Tenma finds the guard dead and the patient missing. Tracking him to a construction site, he witnesses Junkers held at gunpoint by Johan Liebert, now a young man. Despite Tenma's pleas, Johan executes Junkers, then coldly assures Tenma he would never harm the man who saved him. Stunned, Tenma realizes his act of mercy has unleashed a remorseless killer.
Now a suspect in a string of murders, Tenma draws the attention of BKA Inspector Lunge, who doggedly pursues him as the prime culprit. Determined to expose Johan, Tenma seeks out Anna, now living as Nina Fortner with an adoptive family. Though she appears to have moved on, she suffers from recurring nightmares. On her birthday, Tenma warns her of Johan's return, but he fails to prevent Johan from murdering her adoptive parents, re-traumatizing her.
Tenma's investigation reveals Johan's origins in a clandestine East German eugenics project at the 511 Kinderheim, an orphanage that brainwashed children using psychological manipulation and twisted literature. The experiments mold Johan into a calculating killer, his crimes part of a larger scheme to spread chaos. As Tenma uncovers more victims—former Kinderheim inmates, investigators, and civilians—he resolves to stop Johan, despite grappling with the moral implications of killing.
His pursuit spans Germany and beyond, unraveling a labyrinth of conspiracies while evading authorities and Johan's followers. Each revelation strengthens his conviction to end the cycle of violence, even as the psychological toll mounts. Tenma's journey becomes one of redemption, pitting him against the very evil he once saved, as he strives to atone for his past and halt the devastation Johan has wrought.
