In a time of space exploration, the Ganymede, a space station, vanishes into an enigma of space, the Swallows. Captain Cassandra Night of the Ganymede and her crew find themselves on a strange and alien planet, Fellshade. They are caught between the warring inhabitants of this world: a race of humans and the Vapors, an ancient race of sentient, mist-like beings who had conquered Fellshade centuries before. The Vapors want nothing less than total annihilation of the human pestilence. The lords of Fellshade, two brothers, Dacoyt and Kalev are divided one against the other, when a Vaporess, Porra, infects Dacoyt with a deadly poison. Porra and Dacoyt become lovers as the dark magic the Vaporess uses entwines their souls. Kalev and Cassandra and her stranded crew must now join forces in a race to save his brother's soul and Fellshade from total destruction.