After fleeing from Nu-Eden in an effort to escape the lure of the entity who calls herself Xandra, Rob Cameron and his fellow fugitives land on Iceworld, the fifth planet in a distant star system the humans are trying to colonize. Hoping to find sanctuary and start a new life with Valissa, the young woman he loves, Cameron and the others join a small group of stranded scientists in their research station. When a couple of the men decide to go in search of Regina Seagull, one of the scientists who has been abducted by a group of alien savages, Cameron accompanies them into the dark tunnels below the surface of Iceworld. The three men find an alien world in the huge caverns underground and they discover more than just monstrous creatures and Shadow-dwellers.