Mercenary leader Barney Ross and the rest of the Expendables team reunite when Mr. Church hires them for a seemingly easy job. But things go terribly wrong, compelling the mercenaries to seek revenge for a comrade's murder. With the odds against them, Barney and his team are hell-bent on payback and cut a path of destruction through opposing forces, only to encounter an unexpected threat: six pounds of weapons-grade plutonium.