Sylvester Stallone and Robert De Niro trade blows in and out of the boxing ring in Peter Segal's sports comedy drama.

In their heyday, Henry "Razor" Sharp (Stallone) and Billy "The Kid" McDonnen (De Niro) were fierce rivals.

In their first two bouts, each man recorded a decisive victory but before the eagerly anticipated rematch in 1983, Razor announced his retirement without any explanation, effectively ending McDonnen's career as well.

Thirty years later, boxing promoter Dante Slate Jr (Kevin Hart) hires the two men to provide motion capture footage for a video game and in the green screen studio, Sharp and McDonnen get into a brawl.

Video footage of the skirmish goes viral and the two old-timers eventually agree to head back into the ring one final time for the grudge match that never happened.

Razor turns to his old trainer Louis "Lightning" Conlon (Alan Arkin) to get him into peak physical shape while McDonnen draws strength from rebuilding bridges with his estranged biological son, BJ (Jon Bernthal).