Atom: The Beginning is a prequel manga, taking place about 30 years before the Astro Boy series timeline. It began serialization in 2014 in Monthly Heroes Magazine. It is written and drawn by Tetsuro Kasahara, with additional writing by Masami Yuuki and consultation by Macoto Tezuka.
Several years before, there were a series of violent accidents in Tokyo with mysterious earthquakes and fires. These cases have been attributed to robots in some way but still remain unsolved.
In the present, Umataro Tenma and Hiroshi Ochanomizu are university students attempting to make a humanoid robot. Their shared project is the gold and black android A106, who they nickname Six. Tenma and Ochanomizu's theories of a robot that can think and feel like a human are dismissed by potential investors, so the two have to take on part time work and odd jobs to fund their research.
The young men attempt to experiment with A106's emotional capabilities through different experiences, including meeting more primitive robots and entering him into a robot gladiator competition. Along the way, they try to discover more about the strange series of accidents many years ago, but find themselves the targets of a strange and dangerous criminal underworld.
- A106: A humanoid robot being developed by Tenma and Ochanomizu. His AI is limited, but his emotional and mental capabilities have been developing at a rapid rate. He has some physical powers, but only uses them for self defense.
- Hiroshi Ochanomizu: A university student eager to develop a human-like robot. He is determined and energetic but can easily get carried away.
- Umataro Tenma: Hiroshi's classmate, a lazy but intelligent robotics student. He can be arrogant and brash, but is dedicated to robotics at his own pace.
- Ran Ochanomizu: Hiroshi's 14 year old sister, an odd and aloof young girl. She doesn't speak to people she doesn't trust. She also has a crush on A106.
- Moriya Tsutsumi: Tenma and Ochanomizu's school rival. He is a mysterious child prodigy who even built his own enhanced wheelchair.
- Motoko Tsutsumi: Moriya's younger sister, a fashionable and outgoing girl. She is an ally of Tenma and Ochanomizu and studies with them.
Atom: The Beginning began serialization in Monthly Heroes Magazine in November 2014. Since then, three collected volumes have been published in Japan, and a French version has began printing in France and Belgium.