"Needless" is a manga series set in a post-apocalyptic Japan, where a catastrophic event known as the "Blast Hole" has devastated much of the country. The story unfolds in the Black Spot, a quarantined zone filled with dangerous environments and hostile factions. Within this chaotic landscape, individuals known as "Needless" possess supernatural abilities derived from advanced genetic modifications. These powers, referred to as "Fragments," grant them extraordinary capabilities, making them both feared and sought after.

The narrative centers on Adam Blade, a powerful Needless with the ability to copy and use the Fragments of others. Adam is a brash, overconfident fighter who leads a group of Needless in their struggle against the Simeon Organization, a powerful and oppressive force seeking to control the Black Spot and exploit the Needless for their abilities. The Simeon Organization, led by the enigmatic and ruthless Saten, conducts unethical experiments on Needless to enhance their powers, often resulting in grotesque mutations and tragic outcomes.

Joining Adam is Eve Neuschwanstein, a young girl with a mysterious past and a powerful Fragment known as "Zero," which allows her to manipulate gravity. Eve becomes a key figure in the resistance against Simeon, as her abilities and connection to Adam play a crucial role in the unfolding conflict. Other notable characters include Cruz Schild, a non-Needless boy who becomes entangled in the struggle after encountering Adam and Eve. Despite lacking supernatural powers, Cruz's intelligence and resourcefulness make him an invaluable ally.

The plot delves into the origins of the Needless, the true nature of the Blast Hole, and the sinister motives behind Simeon's actions. As the story progresses, alliances are formed, betrayals are uncovered, and the characters confront their own pasts and the moral complexities of their world. The series blends action, science fiction, and dark humor, with intense battles showcasing the diverse and creative applications of the Fragments.

Themes of power, identity, and resistance are explored as the characters navigate a world where survival often depends on strength and cunning. The narrative builds toward a climactic confrontation between Adam's group and the Simeon Organization, revealing secrets that challenge the characters' understanding of their world and their place within it. "Needless" presents a gripping tale of survival and rebellion in a dystopian future, driven by its dynamic characters and intricate plot.