Kuro, alias Black, navigates the sprawling pan-Asian metropolis of Takaramachi as an orphaned street child, embodying a volatile streetwise demeanor and self-declared guardianship over the city he claims as "his town." Enhanced survival instincts and physical mastery fuel his superhuman agility and flight, traits woven into his identity as both defender and embodiment of the urban labyrinth.

His existence intertwines with White (Shiro), an orphaned girl radiating naive innocence and surreal detachment. Their symbiotic bond—dubbed "the Cats"—anchors their survival: Kuro shields White from harm, while her emotional clarity tempers his fractured psyche. Together, they clash with yakuza syndicates aiming to transform Treasure Town into a commercialized dystopia, their partnership a dual blade against encroaching corruption.

Rooted in homelessness, Kuro’s worldview bristles with feral territoriality and disdain for authority. Confrontations with yakuza enforcers and assassins Dragon, Butterfly, and Tiger ignite his brutality, eroding his mental stability until trauma fractures his mind, birthing the "Minotaur"—a savage alter-ego incarnating his repressed rage.

Forced separation from White plunges Kuro into desolation, his grip on reality unraveling as he crafts a crude doll replica of her, a totem of his disintegrating sanity. Reuniting with White forces a reckoning with the Minotaur, a duel between self-destruction and redemption. Triumphing over this inner beast restores their codependent equilibrium, mending his psyche through their unyielding bond.

Secondary figures like Kimura, a morally torn yakuza, mirror Kuro’s ripple effect on Takaramachi’s underworld. His defiant presence sparks covert alliances and shifts in power, framing him as both a scarred product of the city’s underbelly and an unwitting agent of rebellion. The narrative etches him as a paradox—feral yet protective, destructive yet transformative—mirroring the city’s own clash between decay and resilience.