The year is 1972, and the world is in turmoil. The Soviet Union and the Allied Nations are locked in a bitter struggle for global supremacy. The Soviets have developed a powerful new weapon called the Iron Curtain, which can render their troops invulnerable to enemy fire. The Allies know that they must act quickly to prevent the Soviets from using this weapon.

The stage is set for a showdown between the two superpowers. The Soviets have deployed their Iron Curtain device in a heavily fortified base in Siberia. The Allies have sent in a strike force consisting of Chrono Legionnaires, Prism Tanks, and Harrier squadrons to take out the device.

The Chrono Legionnaires are dropped into the base by Chrono transports, and they quickly begin to wreak havoc on the Soviet defenses. They use their time-warping abilities to move through walls and take out key targets with their energy weapons.

Meanwhile, the Prism Tanks move in to provide support. They use their powerful lasers to destroy enemy structures and vehicles from a safe distance. The Harrier squadrons provide air cover, taking out any Soviet aircraft that try to interfere with the mission.

The Soviets are caught off guard by the sudden attack, but they are not without defenses of their own. They send in waves of tanks and infantry to try to stop the Allied advance. However, the Chrono Legionnaires are able to evade most of these attacks with their time-warping abilities.

As the Allies close in on the Iron Curtain device, they receive a critical piece of intelligence from their SpySat satellite. They learn that the device is vulnerable to EMP (electromagnetic pulse) attacks.

The Prism Tanks quickly adjust their targeting systems to fire EMP blasts instead of lasers. They unleash a barrage of EMP blasts at the Iron Curtain device, disabling it just as it is about to activate.

With the Iron Curtain device neutralized, the Allied forces are able to mop up the remaining Soviet defenders and secure the base. The mission is a success, and the world is saved from certain doom.

The operation is later dubbed "Command and Conquer: Showdown" by Allied command, and it becomes one of the most celebrated victories of the war.