Ed Ferald, pilot of the tug Cydonia Zach on the Martian-Lunar run, receives orders from his uncle and boss to take an enigmatic woman as his sole passenger on the return to Mars. When an explosion destroys the passenger ship on which the woman originally booked passage, Ed races against time to rescue the survivors. But he soon finds himself ensnared in plots fed by Earth politics and corporations fighting to preserve their profits even if it means putting the survival of the Martian colony at risk. Ed's passenger is at the center of the fight, though on what side he can't tell. He only knows he has to uncover the plot's conspirators to preserve his Martian home - and to keep from being the next one killed.