The world superpowers of the USA and China must fight together against a well-organized powerful terrorist organization called the Global Liberation Army (GLA).
Each army has it's own weapons and technologies.
USA has good infantry, airforce, and technology.
China has cheap infantry, strong tanks, decent airforce, and nuclear weapons.
GLA has cheap everything, lots of upgrades, and well anti-air.
You fight 9 missions on each side and try dominate or save the world.