GUNS. ALIENS. SPREAD SHOT. CARNAGE.
During the events of Contra III: The Alien Wars, the alien mastermind Red Falcon was finally defeated once and for all. Unfortunately, Red Falcon was only leading the first wave of cosmic uglies. Now, two years later, Black Viper arrives with a fleet of occupational forces in tow. He's none too happy to find Earth still inhabited by soft bipedal mammals instead of the bloodthirsty brood of his home world. As such, he's wasted no time in rectifying the situation.
This puts the people of Earth in one hell of a pickle: submit to alien rule or be crushed under the iron claw of Black Viper. The leaders of Earth chose the next best option-track down the four greatest soldiers who ever lived, transport them to the enemy's base of operations, and then wait for the fireworks. Let's hope you don't disappoint them.