At the beginning of the film, Barney Ross (Sylvester Stallone) led the old buddy Lee (Jason Statham), Gunnar (Dolph Lundgren) and others of the Expendables to hijack the train by helicopter and rescued the imprisoned doctor with a knife (Wesley Snipes). After a short rest, they went to Somalia to sneak into the lair of a certain arms reselling organization to perform the mission. Unexpectedly, Barney discovered that the boss of the organization was Conrad Stonebank (Mel Gibson), a comrade of the Expendables who was supposed to die that year. After a fierce exchange of fire, Stonebank successfully escaped, while the Expendables suffered heavy losses. After this battle, not only the military and the Expendables were furious, but Stonebank was also completely enraged, and the strongest tough guy ushered in a life-and-death duel...