After Noisy Boy was destroyed, Charlie Kenton needed a new robot, so he and Max Kenton went to a junkyard to salvage parts to create a new robot. After Max fell off a hill and got snagged on a robot arm, he discovered that it was an entire robot. Max used a hook connected to their cart to hoist up Atom out of the ditch. Later, Max cleaned off Atom to discover his name written on his chest. After lots of begging from Max, Charlie agreed to take Atom to The Zoo to fight. Max got Atom a fight with Metro, and after taking a pounding in the first round, Atom dodged his previous downfall, and with a quick double uppercut, Atom gave Metro a system malfunction, and won $2,000.
A bystander invited the two to a fight, and Atom went on a winning streak. After defeating robots such as Blacktop, Six Shooter and more, they finally got invited to an official WRB fight with Twin Cities. Despite the fact that the opponent's technology was much more advanced, Atom won yet again, and Max challenged Zeus to a fight. After a very long match, where Atom suffered badly in the first round, but then managed to knock down Zeus thanks to his Shadow Mode, Atom technically lost the Zeus fight by a few points, but he earned the title "The People's Champion".
It can be seen during the final battle.