Burst Angel takes place in a crime ridden future, the streets of Tokyo are patrolled by RAPT, the organization responsible for maintaining peace and order. In this bleak world the citizenry are legally allowed to carry and wield firearms. But so are the criminals. It is RAPT's purpose to dispense quick justice on those that would violate or abuse the law.
But buried deep underground in secret labs, monsters of unimaginable terror are being forged using a new science, having their organic cells fused with machine parts creating the perfect enforcers to endure a future devoid of free will. In response to the rising threat, four brave angels assume the responsibility to defend the defenseless and bring down the underground crime syndicates, as well as the corrupt leaders of RAPT. They are enigmas, but Jo, Sei, Amy, and Meg, are the best change a wounded city has of freeing itself from an even darker future.