The systematic annihilation had taken place a century before when Bontarc had been but a child and Retoc a young man. Karnod, Retoc's father, now dead, had planned the war that defeated the Ofridians, his winning card having been spies in the court of Evalla, Queen of Ofrid. Karnod had been fatally wounded during the last battle and had delegated to his son the task of annihilating the Ofridians and levelling their nation. This task, Retoc accepted with relish, reserving for himself the pleasure of slaying Queen Evalla. Details of the torture to which Retoc subjected the beautiful Evalla were whispered over the planet and it was said the sadistic Retoc had taken photographs of the Queen in her agony to enjoy in later years. It had been the scientific ability of Portox of Ofrid that had engendered the Abarian hatred and jealousy in the first place. Portox used his science for the good of all on the planet Tarth, but when Karnod, Lord of Abaria, struck, no other nation came to Ofrid's aid. Then it was too late, because Abaria's military might greatened as a result of the Ofridian defeat and only an alliance of all other nations could have conquered them. Ironically, Portox had never been captured. Now as the tall gray tower came into view, Bontarc's mind was filled with thoughts of Portox, the Ofridian wizard. It was said that Portox had been able to travel through space to other planets that were known to exist, that he had left Tarth and found safety somewhere across space, first building his tower which would never be destroyed; that a great clock within it was measuring off one hundred years--the time on the planet Tarth of an infant's development into manhood--and that at the end of that span the clock would toll and there would come forth a man to avenge the slaughter of the Ofridians. Bontarc turned suddenly upon the dour Retoc. "Tell me," he said, "is there any truth to the legend that the clock in the tower will toll the end of one hundred years?" "None whatever," the sadistic Abarian snapped. "A rumor passed from the lips of one old woman to another." Bontarc smiled. "Then why are you here? The hundred years are up today." Retoc's hand moved toward his whip-sword. "Are you calling me a liar?" * * * * * Bontarc watched alertly as the blade came partly from its scabbard. "If we fight we may miss the tolling of the clock," he said evenly. With an oath, Retoc pushed the sword back into its scabbard and put sharp heels to his stad's flanks. The animal screamed indignantly and rocketed ahead. Bontarc smiled and turned his car back toward his own group. And now they were assembled and waiting, the curious of the planet Tarth. Would the clock toll as it was rumored Portox had said? Would an avenger come forth to challenge Retoc and his Abarian hordes?