The first native bishop of Mars has been called to Rome. As he makes his way across fifty million miles of space, he encounters a society moving into every corner of the solar system and teeming with every kind of decadence. "We are filling the emptiness with our emptiness," he thinks. A violent fascist opposition is rising, promising to restore humanity to glory. When the bishop gets a mysterious offer to leave the solar system, he is sorely tempted. But if he goes, he may be abandoning Earth to a brutal invasion only he can prevent.