Centuries after a meteor strike blocked the sun and drove humanity into permanent darkness, survivors cluster beneath rare gaps in the cloud cover called Stallites. The people there worship the light as a god, guarded by Sun Priests and their soldiers. Arkhan is one such guardian in the Stallite of Sparta — until an ambush infects him with the Dark Sickness, slowly mutating him into a creature of the dark. His former allies distrust him as he races to find a cure and expose the conspiracy behind the attack.