"Burst Angel" is set in a near-future Japan where crime and violence have escalated to unprecedented levels, prompting the government to legalize the carrying of firearms. The story centers on Jo, a skilled and stoic bounty hunter, and her partner Meg, a cheerful yet deadly sharpshooter. Together, they form the core of a group known as the "Burst Angel" team, which operates outside the law to take down dangerous criminals. The team also includes Amy, a brilliant but eccentric scientist, and Sei, a mysterious and reserved woman with a tragic past.

The narrative begins when Kyohei Tachibana, a young culinary student, is inadvertently drawn into the group's activities after a chance encounter with Jo. Despite his initial reluctance, Kyohei becomes their cook and occasional support, providing a grounded perspective amidst the chaos. The team's missions often involve confronting powerful criminal organizations and rogue elements within the government, with Jo wielding a massive, high-tech handgun named "Beretta M92FS Custom" and Meg using her precision sniping skills.

As the series progresses, the group uncovers a larger conspiracy involving a secretive organization known as RAPT, which seeks to control society through advanced technology and manipulation. The team's battles against RAPT reveal deeper connections to Sei's past and the origins of Jo's combat abilities, which are tied to experimental enhancements. The story explores themes of loyalty, identity, and the moral ambiguity of operating outside the law, with each character grappling with their own motivations and the consequences of their actions.

The series balances episodic missions with an overarching plot, gradually revealing the characters' backstories and the true nature of the threats they face. The dynamic between Jo and Kyohei serves as a focal point, with their contrasting personalities creating both tension and camaraderie. The action-driven narrative is complemented by moments of humor and introspection, providing a multifaceted portrayal of the characters and their world. "Burst Angel" combines elements of cyberpunk, mecha, and Western-inspired gunplay, creating a distinctive blend of genres that drives its storytelling.