In the near future, human boxers have been replaced by giant robots that fight in thrilling matches. Charlie Kenton, a former boxer who has seen better days, tries to survive in this world of steel and circuits, traveling from one fight to another in the hope of hitting the jackpot. However, his luck seems to be running out, and his goal of reaching glory becomes more complicated when he learns of the death of his ex-girlfriend and finds himself responsible for her 11-year-old son, Max, whom he barely knows.
Reluctantly, Charlie accepts the responsibility of taking care of Max, and together they form an unconventional team. Max, who has an innate talent for robots, discovers an old, forgotten robot model in a junkyard, and after a painstaking restoration process, they turn "Atom" into a formidable fighter. As Max becomes more involved in the world of robotic boxing, father and son start to strengthen their family bond.
Over time, the trio faces increasingly powerful rivals and embarks on an exciting journey that takes them to the pinnacle of the world championship. Through this journey, Charlie not only seeks to reclaim his own honor in the ring but also to rediscover his relationship with Max and make sense of a life that seemed lost, all while they fight together against adversity and fate.