"Young Black Jack" is a prequel to Osamu Tezuka's classic manga "Black Jack," written by Yoshiaki Tabata and illustrated by Yūgo Ōkuma. Set in the late 1960s and early 1970s, the series explores the formative years of the enigmatic surgeon Kuroo Hazama, who later becomes the legendary unlicensed doctor known as Black Jack. The narrative delves into his medical training, the origins of his surgical skills, and the events that shape his morally complex worldview.

The story begins with Hazama as a medical student at Meisho University, where his exceptional talent and unorthodox methods set him apart from his peers. His journey is marked by encounters with various medical cases, often involving ethical dilemmas, societal injustices, and the darker aspects of the medical profession. Hazama's character is shaped by his experiences, including a tragic incident involving his childhood friend, Maiko Okamoto, which leaves him scarred both physically and emotionally. This event becomes a pivotal moment, driving his relentless pursuit of medical excellence and his willingness to operate outside conventional boundaries.

Throughout the series, Hazama crosses paths with influential figures in the medical field, including his mentor Dr. Jotaro Honma, who recognizes his potential but struggles to guide him within the constraints of the system. The narrative also introduces recurring characters such as Pinoko, whose origins are tied to one of Hazama's early surgical feats, and Dr. Kiriko, a rival who challenges Hazama's methods and principles. The series frequently explores themes of life and death, the ethics of medical practice, and the tension between personal morality and institutional authority.

Hazama's journey takes him beyond Japan, as he travels to war-torn regions and disaster zones, honing his skills in extreme conditions. These experiences further cement his reputation as a surgeon who operates without regard for rules or regulations, driven solely by his commitment to saving lives. The series also provides insight into the development of his iconic appearance, including the black-and-white hair and facial scars that become his defining traits.

"Young Black Jack" maintains a strong focus on medical drama, with detailed depictions of surgical procedures and the challenges faced by medical professionals. The narrative balances episodic medical cases with an overarching storyline that traces Hazama's evolution into the morally ambiguous yet deeply principled figure known as Black Jack. The series serves as a compelling exploration of the character's origins, offering a deeper understanding of the events and influences that shape his complex persona.