"Jinki" is a science fiction manga series that blends mecha action with intricate character dynamics and a layered narrative. Set in a world where ancient artifacts known as Jinki are unearthed and used to create powerful humanoid machines, the story explores themes of identity, legacy, and the consequences of technological advancement. The narrative unfolds across multiple timelines and perspectives, weaving together the past and present to reveal the larger mysteries surrounding the Jinki.

The central protagonist is Aoba Tsuzaki, a young girl with a passion for building model robots. Her life takes a dramatic turn when she is kidnapped and brought to a secret underground facility in Venezuela. There, she encounters the Jinki, massive humanoid machines piloted by individuals known as "Extended." Aoba is thrust into this hidden world, where she becomes involved in the conflict between two factions: the Angel, who seek to protect humanity, and the Dusk, who aim to harness the Jinki's power for their own purposes. As Aoba learns to pilot a Jinki named Moribito-2, she grapples with her role in the escalating war and her connection to the enigmatic pilot Shizuka Tsuzaki, who shares her surname and may hold the key to her past.

Parallel to Aoba's story is the narrative of Ryohei Ogawa, a young man living in Japan who becomes entangled in the Jinki conflict after encountering a mysterious girl named Satsuki. Ryohei's journey intersects with Aoba's as he uncovers his own ties to the Jinki and the shadowy organizations manipulating events behind the scenes. The series delves into the origins of the Jinki, ancient relics tied to a long-forgotten civilization, and their potential to either save or destroy humanity.

The manga explores the relationships between the characters, particularly the bonds formed between pilots and their Jinki, as well as the moral dilemmas they face in a world where the line between right and wrong is often blurred. Themes of sacrifice, loyalty, and the search for truth are central to the narrative, as the characters navigate a complex web of alliances and betrayals. The story builds toward a climactic confrontation that forces the protagonists to confront their deepest fears and make choices that will shape the future of their world.