"Shikkaku Ishi" is a medical drama anime that centers on Dr. Kenzo Tenma, a skilled Japanese neurosurgeon working in Germany. The narrative begins with Tenma at a prestigious hospital, where his career is on the rise. However, his life takes a dramatic turn when he makes a moral decision to save the life of a young boy, Johan Liebert, over that of a prominent political figure. This choice leads to professional repercussions, as Tenma loses the support of the hospital director and faces a series of setbacks in his career.

The story shifts focus when Johan, the boy Tenma saved, resurfaces years later as a manipulative and enigmatic figure involved in a string of murders. Tenma becomes entangled in a complex web of intrigue as he seeks to uncover the truth behind Johan's actions and his own connection to the events. The narrative explores themes of morality, identity, and the consequences of one's choices, as Tenma grapples with the ethical dilemmas of his profession and the darker aspects of human nature.

Key characters include Nina Fortner, Johan's twin sister, who becomes a pivotal figure in the story as she struggles with her own identity and memories of their shared past. Inspector Lunge, a tenacious and methodical investigator, serves as a foil to Tenma, often clashing with him as he pursues the truth about Johan. The series delves into the psychological and emotional struggles of its characters, weaving a intricate plot that spans multiple countries and timelines.

The anime is notable for its exploration of philosophical questions and its portrayal of the medical and criminal justice systems. It maintains a tense and suspenseful atmosphere, with a focus on character development and the moral ambiguities faced by its protagonists. The story's pacing and structure build toward a climactic confrontation, revealing the deeper connections between the characters and the events that have shaped their lives.