Aster Mackenzie wants to go home. But she's trapped in the Earth's core, where advanced humanoids mine a rare energy source for their home planet, Norona. Worse, she's triggered the Noronian mating fever in Romulus Locke, Innerworld's Chief Administrator. Romulus intends to be Governor of Innerworld but the moment he touches Aster, the fever takes hold, bonding them as soul-mates. Never has the fever affected a Terran, and intimacy between the races is forbidden; a conundrum Romulus has no time to explore. The asteroid heading toward Earth is about to destroy both their worlds. Risking everything, Romulus takes Aster with him to Outerworld to warn Earth's scientists and is captured. Now Aster must face her destiny and convince the powers of Norona to accept a long-hidden secret if her soul-mate is to survive.