After the war, cyborg soldiers known as the Extended were discharged. Juzo Inui is one of them, a man whose body was transformed, his head replaced with a giant gun. With no memory of his previous life--or who replaced his head and why--Inui now scratches out a living in the dark streets of the city as a Resolver, taking on cases involving the Extended.

The war that changed Juzo's life still echoes in the present when the anti-Extended terrorist organization Spitzbergen abducts Juzo's friends. Juzo goes after them, but finds his path blocked by Victor Steinberg, a man with a reputation as a fierce enemy of the Extended. Victor also happens to be Mary's brother, and was once Juzo's personal engineer during the war...