"Appleseed" is a science fiction manga series set in a post-apocalyptic world where humanity struggles to rebuild after a global conflict. The story centers on Deunan Knute, a skilled soldier, and her partner Briareos Hecatonchires, a cyborg, as they navigate the complexities of a society striving for balance between humans, cyborgs, and artificial intelligence. The narrative unfolds in the utopian city of Olympus, a technologically advanced metropolis governed by a supercomputer named Gaia and a council of bioroids—genetically engineered beings designed to maintain peace and order.

Deunan and Briareos are recruited into the ESWAT (Extra Special Weapons and Tactics) team, a special forces unit tasked with handling high-risk missions. Their work often brings them into conflict with various factions, including terrorists, rogue bioroids, and remnants of the old world order. The series explores themes of identity, humanity, and the ethical implications of technological advancement, as Deunan and Briareos grapple with their roles in a society where the lines between human and machine are increasingly blurred.

Key characters include Hitomi, a bioroid and close ally of Deunan, who serves as a bridge between humans and bioroids, and Uranos, a charismatic but morally ambiguous figure who challenges the status quo of Olympus. The plot frequently delves into political intrigue, as the stability of Olympus is threatened by internal and external forces, including conspiracies aimed at undermining Gaia's authority and the fragile coexistence of humans and bioroids.

The series is notable for its intricate world-building, blending action-packed sequences with philosophical inquiries into the nature of humanity and the consequences of technological dependency. Through its exploration of a society in transition, "Appleseed" presents a compelling narrative that examines the challenges of maintaining harmony in a world where the boundaries between organic and synthetic life are increasingly indistinct.