Dr. Kenzou Tenma, an esteemed neurosurgeon engaged to the daughter of his hospital director, is on track to advance his career. However, his life changes after receiving a call from the hospital director instructing him to abandon his current surgery and perform brain surgery on a famous performer. Although his superiors cheer him on, a poor immigrant worker dies due to the switch, causing Dr. Tenma to question his moral compass. When faced with a similar situation, Dr. Tenma chooses to perform surgery on Johan Liebert instead of the town's mayor. This decision has negative consequences for him, including a loss of social standing. Yet, Dr. Tenma's standing is restored after the hospital director and two doctors die under strange circumstances. Despite his release for lack of evidence to convict him, Dr. Tenma suffers the consequences of his choice and eventually becomes hospital director. Nine years later, Dr. Tenma saves the life of a criminal, which brings back his past. He once again confronts the monster he had operated on and realizes he needs to make amends for the chaos caused by his decision. His pursuit of redemption becomes his new mission.