Set in 2641 AD, five years after the "Alien Wars", and three years after the deaths of Black Viper and Emperor Demon Gava, alien cells kept at a military research facility are stolen in a terrorist attack. The Contra Hard Corps, comprised of Ray Poward, Sheena Etranzi, Brad Fang and Browny, are assigned to the investigation. They discover that retired Major Bahamut is implicated, and that he has conspired with Dr. Geo Mandrake to create a biological weapon using the stolen alien cells, as a form of leverage to overthrow the present government. Through their efforts, the Hard Corps manage to thwart Major Bahamut's plans and restore peace once a more.