Plot

The Expendables include leader Barney Ross (Sylvester Stallone), knife specialist Lee Christmas (Jason Statham), hand-to-hand combat specialist Yin Yang (Jet Li), heavy-weapons specialist Hale Caesar (Terry Crews), demolitions expert Toll Road (Randy Couture), the unstable Gunner Jensen (Dolph Lundgren), and sniper Billy the Kid (Liam Hemsworth) who is the team's newest recruit, and Ross' protege.

The Expendables are deployed to Nepal to rescue Dr. Zhou, a hostage. Zhou is a Chinese businessman who was captured by the Nepalese militia. The Expendables hit the militia compound with their heavily armed convoy. The militia defenses and troops are no match for the heavy weapons deployed by the Expendables.

The Expendables had come very well prepared for all the obstacles that the militia could put in their path including armored plated convoy, heavy caliber machine guns, rocket launched grenades, and a thick steel bar mounted on the front of a vehicle to break through compound walls to get to the hostage. When they are attacked by a chopper, Ross uses a ramp to launch a bike at the chopper and brings it down.

They also rescue the captured mercenary Trench (Arnold Schwarzenegger), Ross' rival. Trench had also taken a contract to rescue Zhou, but his team was captured instead. Trench goes his own way for escape, while the Expendables use a power line as a zip line from the roof of the compound to escape into the surrounding jungle. When Ross is surrounded by the militia, Billy takes them out from his hidden sniper position.

The team then uses a boat to escape the jungle and are pursued by the militia in fast attack boats. Ross arrives with his sea plane that he lands in the middle of the river, while Billy takes out all the soldiers in the attack boats. Ross encounters a militia fortification in middle of the river (which starts firing on the sea plane) and takes it out with a cannon loaded in the front of his sea plane and operated by Christmas. Ross manages to get the plane back up in the air before it hits a barrage on the river.

Yang leaves the group and jumps out of the plane with Zhou, as the plane flies over China, to escort him back to China. After returning to New Orleans, Billy tells Ross that he intends to retire at the end of the month and live with his girlfriend Sophia. Ross is sad to see Billy leave as Billy is an excellent sniper.

Later, Ross is forced to accept a mission from CIA operative Mr. Church (Bruce Willis) to retrieve an item from a downed airplane in Albania. On a previous mission, Ross killed a CIA agent (who was corrupt) and stole $ 5 million from Church. Church vows to put Ross and his entire crew in Guantanamo Bay prison, if he does not accept the new mission. Church sends technical expert Maggie Chan (Yu Nan) with the team. In Albania the Expendables retrieve the item from a crashed plane. The item was locked behind a safe, which access codes that changed frequently. Maggie was on the team to disable the safe and get the item out.

The Expendables are then ambushed by international criminal and arms dealer Jean Vilain (Jean-Claude Van Damme), his right-hand man Hector (Scott Adkins) and his mercenary group (the Sangs).

The Sangs capture Billy, who was supposed to be watching over the group from a vantage point. Vilain demands the item in exchange for Billy's life. The team gives up the item, but Vilain stabs Billy through the heart with Ross's own knife and flees with the Sangs by helicopter. Ross recovers a note for Sophia from Billy's body. The team buries their fallen comrade, swearing revenge on Vilain. Church contacts Ross on radio and threatens dire consequences if the computer is not delivered. Ross admonishes Church for using the Expendables for his dirty work, due to which Billy died, and tells him that they are done working for him.

Maggie tells them that the item is a computer, with the location of five tons of refined plutonium abandoned in a mine by the Soviet Union after the Cold War. Vilain intends to retrieve the plutonium and sell it. The Expendables are able to weakly track the computer's signal with Maggie's help and follow Vilain, who leads them to Bulgaria. The Expendables stay overnight at an abandoned Russian military base.

Next morning, the team is ambushed by the Sangs and a tank. After the Expendables run out of ammunition, they are saved by Booker (Chuck Norris) (Ross' old friend), who quickly eliminates both the Sangs and the tank. Before he departs, Booker informs the group of a nearby village whose residents dislike Vilain. Meanwhile, Hector and Vilain dig up the plutonium and begin collecting it.

In the village, the Expendables find several armed female villagers guarding their children from Vilain's forces. The local inhabitants are taken and put to work as slaves in the mine, never returning since they die from radiation poisoning in the mines, and the women plead for the Expendables' help.

The Sangs arrive for more villagers but are ambushed by the Expendables and killed. After locating Vilain and the mine, the team assaults the area with their plane before deliberately crashing into the mine. The team saves the enslaved miners from execution, but Vilain and Hector escape with the plutonium. Vilain remotely detonates explosive charges in the mine, which collapses, trapping the miners and the Expendables.

Church and Trench arrive, freeing the miners and the team, and join the Expendables to pursue Vilain. The group intercepts Vilain and his men at an airport as he prepares to leave by plane. Joined again by Booker, the Expendables, Trench and Church engage the Sangs in battle. Christmas decapitates Hector, while Ross and Vilain fight hand-to-hand. Ross defeats Vilain, stabbing him and avenging Billy.

In the aftermath, Ross is given an old Antonov An-2 biplane by Church. Church, Maggie, Booker and Trench then leave the team. In France, Sophia (Nikolette Noel) discovers a box on her doorstep with a large sum of money and Billy's letter. As the Expendables depart in the plane, they propose a final toast to Billy.