Flynn Guffin's violet-eyed mother disappeared shortly after his birth. He's grown to young manhood, looking after his grief-stricken father and working Pale Haven's fungus mines. When a strangle root attack triggers latent power, his grey eyes turn violet. Shunned by superstitious neighbours, he stows aboard an airship bound for Violet City, seeking an exiled friend who owes him a favour and hoping to find answers to his mysterious genetic inheritance. Revolution brews in the decadent metropolis languishing in the shadow of Cathedral Mountain, as foretold in the paintings of a precocious ten-year-old girl. Street gangs clash with raven-masked militia, and an aristocrat stages a cruel spectacle in his Torture Garden to feed the energy parasites he worships. Airships and hot-air balloons glide above scenes of depravity and violence. With the aid of Professor Mercuria (his mother's former mentor), the precognitive child, and the street ruffian he's fallen for, Flynn discovers why the mountain-dwelling life suckers hunt humans with violet eyes, his awful destiny, and the true power lurking behind the Naal Priests' death cult.