The game starts as Marlowe is brought from a helicopter to the front lines. Preston meets his new squad-mates and quickly learns from Redford that Bad Company is much less formal than other military units. An artillery barrage wipes out the convoy, along with the squad's truck. This is where the player learns to look, jump, crouch, shoot, fire grenades, and repair vehicles. Mike-One-Juliet, the dispatch officer, sends Bravo-One Charlie (Preston's squad), to wipe out an artillery battery used by the Russians and later to use them to shell the incoming vehicles attacking Juneau convoy. The squad is then sent to clear a Russian-occupied river crossing when the Russians destroy the bridge. Bravo-One is then sent to clear a Russian-occupied farm before being extracted, but when their helicopter is shot down by anti-aircraft fire, they are then sent to destroy the anti-air emplacements and raid another Russian-occupied farm in Juneau Convoy's path. When the squad joins Juneau convoy, it is attacked by another artillery barrage. They barely manage to escape, and are sent to destroy radar jammers to let an airstrike destroy the artillery. After the airstrike finishes, Bravo-One clears out any survivors and encounter the Legionnaire Mercenaries, a mercenary group said to be the strongest military organization in the world. Haggard finds a gold bar in the suit of a dead Legionnaire mercenary, starting their interest in the Legionnaire's gold.

On what was supposed to be Redford's last mission before retirement, the squad is sent to move through more Russian territory when they find a house with the Legionnaires' insignia on a sign in front, Acta Non Verba - Latin for "Action, Not Words". Haggard sends Marlowe inside to check out the house. There, Marlowe finds the first case of gold. The squad had been given orders to destroy fuel and missile storage facilities and to then meet up with a US Armored Division and escort them into the Russian-held city of Zabograd. Bravo-One Charlie is sent ahead to clear the pass of anti-tank missile launchers and to escort the tanks to the other side of the town where the main assault is to take place. The squad is then sent to destroy a Russian radio outpost before they call for reinforcements, but they are too late as the call is made and more Russian forces arrive. Just then, a rocket is heard hitting a US tank nearby, to which Mike-One-Juliet sends the squad to defend it from the enemy reinforcements until more US forces arrive. Mike-One-Juliet then sends them to a harbor full of suspicious activity and says that if they do a good job, she could get them out the company and in to a better unit. They arrive at the harbor, but find that it is full of mercenaries. The squad, led by Haggard and the thought of gold, fight their way through, but after checking the bodies, find nothing. They then spot some trucks and watch them drive away. As they go, a bar of gold drops out of the back and they become determined to follow them and retrieve the gold.

Soon after arriving on the border of Serdaristan, Bravo-One Charlie finds the trucks crossing the border and realize they can't follow it any longer as Serdaristan is neutral in the war. Overcome with greed, Haggard runs across the border, "single-handedly invading a neutral country". When asked why they were in Serdaristan, Redford Tells Mike-One-Juliet that it was his idea to wipe out a potential threat. Redford's tour of duty is consequentially increased by another year. This pushes Redford over the edge and he tells the squad that they're going AWOL. They first destroy three radio transmission towers to cover their tracks. Redford then figures out that the gold is in another harbor. After they fight their way through, they are just about to enter the Legionnaire's cargo ship when the US Army shows up and captures them.

The army sends Bravo-One Charlie on a top-secret mission to go into Serdaristan and capture the President, who they believe is selling arms to the Russians. However, the squad realizes that Serdaristan is no longer neutral when they witness their chopper being shot down by Serdaristani anti-air emplacements. Mike-One-Juliet sends them to destroy the emplacements so that another chopper can be flown in to extract them with the President once they capture him. Later on, Miss July sees lots of activity at the Presidential Palace, so she sends Bravo-One a laser designator and directs them to an enemy weapons cache. They make their way through the President's personal golf course and head towards the Presidential Palace. Once they arrive, they find that the grounds are crawling with Legionnaires. They fight their way in to get the President but when Redford calls for an evac chopper, Mike-One-Juliet tells them that she cannot because the Army ditched them and that they were on their own. President Serdar then tells them he has a personal Mi-24 Hind that they could use to escape from Serdaristan.

The squad then takes the President's helicopter and use it to destroy Serdaristan's military infrastructure. Their helicopter soon runs out of fuel and they arrive at a refueling station. As there is no source of fuel near the helicopter, Marlowe and Haggard are forced to drive an M939 truck carrying fuel to the Hind. Haggard then accidentally pours the fuel into the cooling unit, making Sweetwater have to fix it due to Haggard's incompetence. They hold off Serdaristan Army reinforcements and as several BMD-3's starting moving towards them, Sweetwater fixes the fuel problem and they escape. The President than asks Bravo-One to bring him to Russia for his exile and as he informs them about where the gold is, but the Legionnaire appears in his personal Ka-52 and shoots down the pimped-out Hind.

Marlowe wakes up after the crash, only to find his squad-mates and the President missing. He tries contacting Mike-1-Juliet, to which she guides him to several areas where she thinks the squad is located. In one of the areas, there is a video screen of the Legionnaire interrogating President Serdar and later shooting the camera after he finds out that it was recording. Marlowe makes his way through a large Russian Army force to get to the monastery located on top of a mountain, where he finds his squad did not actually need much saving as they had just escaped captivity. Together, they all head back down the mountain, evading Russian reinforcements as they head towards the sea where they may find a boat to escape with. After fighting tanks, APCs and a Russian Hind, they find the President in a small port about to be executed by the Legionnaires. The squad manages to stop the execution and, with the President, take a boat to Sadiz, along the Caspian Sea.

The President gets his exile from his country on a small island near Sadiz while the squad goes after the gold. After fighting a large number of Middle Eastern Coalition soldiers and tanks, Bravo-One Charlie overhears that the US army is pushing onward toward the port of Sadiz, where the gold is located on the Legionnaire's tanker. The squad then destroys two bridges to prevent the Army from getting there first. When they reach the port, they find the stash of gold in a warehouse. While they were staring in awe at the piles of gold, the Legionnaire shows up and attacks the squad in his helicopter. They race towards the end of a pier where Sweetwater believes and anti-aircraft gun is located. However, just as Marlowe is about to man the VADS, the Legionnaire destroys it. Marlowe finds a M2 Carl Gustav helipad above and with a few well-placed shots, destroys the Ka-52. They return to the warehouse to find the US Army packing up all of the gold in the warehouse in to trucks. Just when the squad is about to leave in disappointment, a US Army Officer notices them and gives them orders to drive one of the trucks full of "scrap metal" with the convoy. They follow the convoy for a while until they turn off to a side road and speed away, each talking about how they will spend their share of gold. The last scene shows the Legionnaire getting out of his chopper's wreckage with a look of vengeance in his eyes.