"ATOM: The Beginning" is a prequel to Osamu Tezuka's iconic "Astro Boy," exploring the origins of robotics and artificial intelligence in a futuristic Japan. The story is set in a world where robotics technology is rapidly advancing, and the narrative centers on two young scientists, Hiroshi Ochanomizu and Umatarō Tenma, who are students at the prestigious National Institute of Technology. Their shared ambition is to create a robot capable of surpassing human intelligence and achieving true autonomy.

The duo begins their journey by developing A106, a prototype robot with advanced cognitive abilities. A106, later named "Six," exhibits remarkable potential, displaying emotions, curiosity, and a desire to learn about the world. However, Six's development is not without challenges, as the robot's growing sentience raises ethical and philosophical questions about the nature of artificial life. The story delves into the complexities of human-robot relationships, the responsibilities of creators, and the societal implications of advanced robotics.

As Hiroshi and Tenma work to refine Six, they face opposition from various factions, including rival researchers, corporate interests, and government entities. These groups view Six as either a threat or a tool for their own agendas, leading to conflicts that test the scientists' resolve and principles. The narrative also explores the contrasting personalities of the two protagonists: Hiroshi, who is compassionate and idealistic, and Tenma, who is pragmatic and driven by ambition. Their differing approaches to robotics and ethics create tension but also drive the story forward.

The manga incorporates elements of science fiction, action, and drama, with a focus on the technical and moral challenges of creating sentient machines. It pays homage to Tezuka's original work while expanding on the lore of the "Astro Boy" universe, offering a deeper exploration of the events and characters that precede the creation of Astro Boy. The story balances intellectual themes with engaging plotlines, making it accessible to both fans of the original series and newcomers to the franchise.