Set in the year 2100, Gundress finds the recently constructed Bayside City functioning as Japan's busiest international port, and therefore also the one most prone to terrorist activity. To combat the terrorists, a former policewoman named Takako forms the Angel Arms Company, a quasi-militaristic force that used armoured suits to protect the city's interests. When the Mayor is assassinated, the Angel Arms decide to protect the city's most powerful crime lord, hoping that he will provide them with the information to bring down the international terror ring that plagues the city.