In 2020, human boxers are replaced by robots. Charlie Kenton (Hugh Jackman), a former boxer, owns “Ambush”, but loses it in a fight against a bull belonging to promoter and carnival owner Ricky (Kevin Durand), who sees Charlie’s mere existence as a joke, partially because he physically beat Charlie the last time they competed for bailing on the bet. Having made a bet that Ambush would win, Charlie now has a debt to Ricky—which he runs out on.
After the fight, Charlie learns that his ex-girlfriend died and he must attend a hearing deciding the future of their son, Max (Dakota Goyo) to which Charlie has almost zero contact with since he was born. There, Max’s aunt, Debra (Hope Davis), and her wealthy husband, Marvin (James Rebhorn), request full custody, which Charlie concedes for $100,000, half in advance, on the condition that Charlie retains Max for three months while they are on vacation and the other half when they return. Thereupon, Charlie, Max, and Bailey Tallet (Evangeline Lilly), the daughter of Charlie’s former boxing coach, acquire the once-famous “Noisy Boy”, but it is destroyed in a subsequent fight against “Midas”. Attempting to scavenge parts to make a new robot from a junkyard, Max discovers “Atom”, an obsolete but intact sparring robot designed to withstand severe damage, and is capable of mirroring opponent and handler movements and storing them in its memory due to its rare “shadow function” mode.