That was their error. The Senior-Gard hurled to the door, catching the handle with his chained hands. Keeven turned. Too late! The door slammed shut. The Olman struck at the door with fists like battering rams. To no avail. The gyro hummed, lifted straight up, and went winging back toward the Barrier.

"They're going for reinforcements!" Agitated Allyn turned to Jon. "They'll return and attack your town."

The Elder's eyes twinkled. "There is no fear in York. Come to my dwelling. You will eat, and perhaps we can help you find what you seek."

He led the way to one of the strange red colored houses. Inside were fabric hangings over the windows, and fabric covering the floor and furniture. Allyn found it colorful, but too barbaric for his own austere taste. The Elder's mate, a silver haired woman with friendly blue eyes came to serve them.

Over the dishes of unfamiliar, but steamingly good food, Jon told of the ancient records preserved in the archives. The records told of the Originals of the Earth, a mighty but warlike race. Their terrible weapons had laced the earth with Bands of Radiation whose rays had changed the genes of mankind. The Numen were evolved from this. But many Originals had gone underground, in lead-impregnated shelters, staying there for countless generations. These were the Olmen, untouched by the first and strongest radiations.

In York, when the Olmen came again to the surface, they found the Numen decreasing as their women died in childbirth. At first there was antagonism between the groups but, on several occasions younger and more lustful Numen seized Olwomen, and from that mating it was discovered that only in cross-breeding was there survival.

"Our medics," the Elder explained, "have found that pure breeding of Numen created a negative factor in the blood of the unborn child. These negative antibodies erupted into the positive bloodstream of the mother, causing a jaundiced condition that affects the brain, leading to death in labor. Yet that same X-condition goes through transformation in the baby's system after the birth eruption so that, by the age of one year, the child is of positive blood. The weird X-factor holds true only in pure Numan breeding, seldom in cross-breeding."

But Keeven said moodily, "The Numen will not believe this. They will come with their gyros to destroy York for heresey." He leaned across the table. "But there are weapons," he told the Elder. "Our legends say there are weapons to blast the Nyloplast dome. If we are the victors, Numen will have to listen."

Jon shook his head. "There are no weapons. They were destroyed by the Originals when they saw how they had destroyed themselves. But there is a way." He looked at Allyn. "It is a hard way—and dangerous, but perhaps you can do it."

And he told them.