In a future where a single family's company holds title to 90 percent of the Earth's dry land, ordinary humans are considered parasites on the planet's surface. Persona Century Corporation tolerates their presence, but does whatever it wishes with Earth, murdering villages on a whim and brutally punishing any dissension or resistance. Terrifying "enhanced men" assassins and pinpoint satellite strikes enforce the Corporation's monopoly without mercy.
A few hopeless rebels fight back, and a small group of self-styled "juvenile delinquents" revel in their freedom in Tokyo's remaining free area, the city's Darkside. But the balance of power is firmly fixed until a strange, beautiful, vaguely Victorian man steps out of the alternate dimension that Persona had trapped him in. Taking up residence in Darkside, he names himself after the city and begins offering "Dream Treatments" for those in need of "renewal."
Darkside doesn't have a stated agenda and seems content with a passive role. But his mere presence seems to galvanize stated neutrals like gangleader Mai and former nurse Selia. And as his strange powers give their nascent struggle a fighting chance, the abrupt entrance of a badly-wounded rebel "terrorist" gives it focus and meaning. But Persona Century has noticed both new arrivals and has every intention of clearing the parasites off its land -- at least, the ones that don't know their proper place.